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+anno_start	anno_end	anno_text	entity_type	sentence	section
+21	25	Mep2	protein_type	Structural basis for Mep2 ammonium transceptor activation by phosphorylation	TITLE
+26	46	ammonium transceptor	protein_type	Structural basis for Mep2 ammonium transceptor activation by phosphorylation	TITLE
+61	76	phosphorylation	ptm	Structural basis for Mep2 ammonium transceptor activation by phosphorylation	TITLE
+0	13	Mep2 proteins	protein_type	Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development.	ABSTRACT
+18	24	fungal	taxonomy_domain	Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development.	ABSTRACT
+25	37	transceptors	protein_type	Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development.	ABSTRACT
+69	77	ammonium	chemical	Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development.	ABSTRACT
+89	95	fungal	taxonomy_domain	Mep2 proteins are fungal transceptors that play an important role as ammonium sensors in fungal development.	ABSTRACT
+0	4	Mep2	protein_type	Mep2 activity is tightly regulated by phosphorylation, but how this is achieved at the molecular level is not clear.	ABSTRACT
+38	53	phosphorylation	ptm	Mep2 activity is tightly regulated by phosphorylation, but how this is achieved at the molecular level is not clear.	ABSTRACT
+15	39	X-ray crystal structures	evidence	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+47	51	Mep2	protein_type	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+69	93	Saccharomyces cerevisiae	species	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+98	114	Candida albicans	species	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+170	182	transporters	protein_type	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+187	205	not phosphorylated	protein_state	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+221	227	closed	protein_state	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+229	237	inactive	protein_state	Here we report X-ray crystal structures of the Mep2 orthologues from Saccharomyces cerevisiae and Candida albicans and show that under nitrogen-sufficient conditions the transporters are not phosphorylated and present in closed, inactive conformations.	ABSTRACT
+16	20	open	protein_state	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+21	30	bacterial	taxonomy_domain	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+31	52	ammonium transporters	protein_type	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+54	72	non-phosphorylated	protein_state	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+73	77	Mep2	protein_type	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+97	114	cytoplasmic loops	structure_element	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+123	140	C-terminal region	structure_element	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+142	145	CTR	structure_element	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+174	178	exit	site	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+186	193	channel	site	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+215	219	His2	residue_name_number	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+227	241	twin-His motif	structure_element	Relative to the open bacterial ammonium transporters, non-phosphorylated Mep2 exhibits shifts in cytoplasmic loops and the C-terminal region (CTR) to occlude the cytoplasmic exit of the channel and to interact with His2 of the twin-His motif.	ABSTRACT
+4	24	phosphorylation site	site	The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	ABSTRACT
+32	35	CTR	structure_element	The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	ABSTRACT
+39	57	solvent accessible	protein_state	The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	ABSTRACT
+75	100	negatively charged pocket	site	The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	ABSTRACT
+121	133	channel exit	site	The phosphorylation site in the CTR is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	ABSTRACT
+4	21	crystal structure	evidence	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+25	50	phosphorylation-mimicking	protein_state	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+51	64	Mep2 variants	mutant	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+70	81	C. albicans	species	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+121	130	conserved	protein_state	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+172	175	CTR	structure_element	The crystal structure of phosphorylation-mimicking Mep2 variants from C. albicans show large conformational changes in a conserved and functionally important region of the CTR.	ABSTRACT
+58	68	eukaryotic	taxonomy_domain	The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.	ABSTRACT
+69	77	ammonium	chemical	The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.	ABSTRACT
+91	106	phosphorylation	ptm	The results allow us to propose a model for regulation of eukaryotic ammonium transport by phosphorylation.	ABSTRACT
+1	14	Mep2 proteins	protein_type	 Mep2 proteins are tightly regulated fungal ammonium transporters.	ABSTRACT
+37	43	fungal	taxonomy_domain	 Mep2 proteins are tightly regulated fungal ammonium transporters.	ABSTRACT
+44	65	ammonium transporters	protein_type	 Mep2 proteins are tightly regulated fungal ammonium transporters.	ABSTRACT
+29	47	crystal structures	evidence	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+51	57	closed	protein_state	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+68	81	Mep2 proteins	protein_type	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+123	145	by comparing them with	experimental_method	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+150	154	open	protein_state	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+155	176	ammonium transporters	protein_type	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+180	188	bacteria	taxonomy_domain	Here, the authors report the crystal structures of closed states of Mep2 proteins and propose a model for their regulation by comparing them with the open ammonium transporters of bacteria.	ABSTRACT
+0	12	Transceptors	protein_type	Transceptors are membrane proteins that function not only as transporters but also as receptors/sensors during nutrient sensing to activate downstream signalling pathways.	INTRO
+17	34	membrane proteins	protein_type	Transceptors are membrane proteins that function not only as transporters but also as receptors/sensors during nutrient sensing to activate downstream signalling pathways.	INTRO
+20	32	transceptors	protein_type	A common feature of transceptors is that they are induced when cells are starved for their substrate.	INTRO
+39	63	Saccharomyces cerevisiae	species	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+64	76	transceptors	protein_type	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+81	90	phosphate	chemical	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+92	97	Pho84	protein	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+100	111	amino acids	chemical	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+113	117	Gap1	protein	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+123	131	ammonium	chemical	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+133	137	Mep2	protein	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+140	152	transceptors	protein_type	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+166	183	higher eukaryotes	taxonomy_domain	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+210	219	mammalian	taxonomy_domain	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+220	225	SNAT2	protein	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+226	248	amino-acid transporter	protein_type	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+257	262	GLUT2	protein	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+263	282	glucose transporter	protein_type	While most studies have focused on the Saccharomyces cerevisiae transceptors for phosphate (Pho84), amino acids (Gap1) and ammonium (Mep2), transceptors are found in higher eukaryotes as well (for example, the mammalian SNAT2 amino-acid transporter and the GLUT2 glucose transporter).	INTRO
+71	83	transceptors	protein_type	One of the most important unresolved questions in the field is how the transceptors couple to downstream signalling pathways.	INTRO
+92	103	transporter	protein_type	One hypothesis is that downstream signalling is dependent on a specific conformation of the transporter.	INTRO
+0	4	Mep2	protein_type	Mep2 (methylammonium (MA) permease) proteins are ammonium transceptors that are ubiquitous in fungi.	INTRO
+5	44	(methylammonium (MA) permease) proteins	protein_type	Mep2 (methylammonium (MA) permease) proteins are ammonium transceptors that are ubiquitous in fungi.	INTRO
+49	70	ammonium transceptors	protein_type	Mep2 (methylammonium (MA) permease) proteins are ammonium transceptors that are ubiquitous in fungi.	INTRO
+94	99	fungi	taxonomy_domain	Mep2 (methylammonium (MA) permease) proteins are ammonium transceptors that are ubiquitous in fungi.	INTRO
+19	52	Amt/Mep/Rh family of transporters	protein_type	They belong to the Amt/Mep/Rh family of transporters that are present in all kingdoms of life and they take up ammonium from the extracellular environment.	INTRO
+73	93	all kingdoms of life	taxonomy_domain	They belong to the Amt/Mep/Rh family of transporters that are present in all kingdoms of life and they take up ammonium from the extracellular environment.	INTRO
+111	119	ammonium	chemical	They belong to the Amt/Mep/Rh family of transporters that are present in all kingdoms of life and they take up ammonium from the extracellular environment.	INTRO
+0	5	Fungi	taxonomy_domain	Fungi typically have more than one Mep paralogue, for example, Mep1-3 in S. cerevisiae.	INTRO
+35	38	Mep	protein_type	Fungi typically have more than one Mep paralogue, for example, Mep1-3 in S. cerevisiae.	INTRO
+63	69	Mep1-3	protein	Fungi typically have more than one Mep paralogue, for example, Mep1-3 in S. cerevisiae.	INTRO
+73	86	S. cerevisiae	species	Fungi typically have more than one Mep paralogue, for example, Mep1-3 in S. cerevisiae.	INTRO
+15	28	Mep2 proteins	protein_type	Of these, only Mep2 proteins function as ammonium receptors/sensors in fungal development.	INTRO
+41	49	ammonium	chemical	Of these, only Mep2 proteins function as ammonium receptors/sensors in fungal development.	INTRO
+71	77	fungal	taxonomy_domain	Of these, only Mep2 proteins function as ammonium receptors/sensors in fungal development.	INTRO
+41	45	Mep2	protein	Under conditions of nitrogen limitation, Mep2 initiates a signalling cascade that results in a switch from the yeast form to filamentous (pseudohyphal) growth that may be required for fungal pathogenicity.	INTRO
+184	190	fungal	taxonomy_domain	Under conditions of nitrogen limitation, Mep2 initiates a signalling cascade that results in a switch from the yeast form to filamentous (pseudohyphal) growth that may be required for fungal pathogenicity.	INTRO
+25	37	transceptors	protein_type	As is the case for other transceptors, it is not clear how Mep2 interacts with downstream signalling partners, but the protein kinase A and mitogen-activated protein kinase pathways have been proposed as downstream effectors of Mep2 (refs).	INTRO
+59	63	Mep2	protein	As is the case for other transceptors, it is not clear how Mep2 interacts with downstream signalling partners, but the protein kinase A and mitogen-activated protein kinase pathways have been proposed as downstream effectors of Mep2 (refs).	INTRO
+228	232	Mep2	protein	As is the case for other transceptors, it is not clear how Mep2 interacts with downstream signalling partners, but the protein kinase A and mitogen-activated protein kinase pathways have been proposed as downstream effectors of Mep2 (refs).	INTRO
+14	18	Mep1	protein	Compared with Mep1 and Mep3, Mep2 is highly expressed and functions as a low-capacity, high-affinity transporter in the uptake of MA.	INTRO
+23	27	Mep3	protein	Compared with Mep1 and Mep3, Mep2 is highly expressed and functions as a low-capacity, high-affinity transporter in the uptake of MA.	INTRO
+29	33	Mep2	protein	Compared with Mep1 and Mep3, Mep2 is highly expressed and functions as a low-capacity, high-affinity transporter in the uptake of MA.	INTRO
+37	53	highly expressed	protein_state	Compared with Mep1 and Mep3, Mep2 is highly expressed and functions as a low-capacity, high-affinity transporter in the uptake of MA.	INTRO
+130	132	MA	chemical	Compared with Mep1 and Mep3, Mep2 is highly expressed and functions as a low-capacity, high-affinity transporter in the uptake of MA.	INTRO
+13	17	Mep2	protein	In addition, Mep2 is also important for uptake of ammonium produced by growth on other nitrogen sources.	INTRO
+50	58	ammonium	chemical	In addition, Mep2 is also important for uptake of ammonium produced by growth on other nitrogen sources.	INTRO
+87	95	nitrogen	chemical	In addition, Mep2 is also important for uptake of ammonium produced by growth on other nitrogen sources.	INTRO
+26	31	human	species	With the exception of the human RhCG structure, no structural information is available for eukaryotic ammonium transporters.	INTRO
+32	36	RhCG	protein	With the exception of the human RhCG structure, no structural information is available for eukaryotic ammonium transporters.	INTRO
+37	46	structure	evidence	With the exception of the human RhCG structure, no structural information is available for eukaryotic ammonium transporters.	INTRO
+91	101	eukaryotic	taxonomy_domain	With the exception of the human RhCG structure, no structural information is available for eukaryotic ammonium transporters.	INTRO
+102	123	ammonium transporters	protein_type	With the exception of the human RhCG structure, no structural information is available for eukaryotic ammonium transporters.	INTRO
+21	30	bacterial	taxonomy_domain	By contrast, several bacterial Amt orthologues have been characterized in detail via high-resolution crystal structures and a number of molecular dynamics (MD) studies.	INTRO
+31	34	Amt	protein_type	By contrast, several bacterial Amt orthologues have been characterized in detail via high-resolution crystal structures and a number of molecular dynamics (MD) studies.	INTRO
+101	119	crystal structures	evidence	By contrast, several bacterial Amt orthologues have been characterized in detail via high-resolution crystal structures and a number of molecular dynamics (MD) studies.	INTRO
+136	154	molecular dynamics	experimental_method	By contrast, several bacterial Amt orthologues have been characterized in detail via high-resolution crystal structures and a number of molecular dynamics (MD) studies.	INTRO
+156	158	MD	experimental_method	By contrast, several bacterial Amt orthologues have been characterized in detail via high-resolution crystal structures and a number of molecular dynamics (MD) studies.	INTRO
+15	25	structures	evidence	All the solved structures including that of RhCG are very similar, establishing the basic architecture of ammonium transporters.	INTRO
+44	48	RhCG	protein	All the solved structures including that of RhCG are very similar, establishing the basic architecture of ammonium transporters.	INTRO
+106	127	ammonium transporters	protein_type	All the solved structures including that of RhCG are very similar, establishing the basic architecture of ammonium transporters.	INTRO
+18	24	stable	protein_state	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+25	32	trimers	oligomeric_state	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+44	51	monomer	oligomeric_state	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+62	75	transmembrane	structure_element	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+77	79	TM	structure_element	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+81	88	helices	structure_element	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+95	110	central channel	site	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+132	140	ammonium	chemical	The proteins form stable trimers, with each monomer having 11 transmembrane (TM) helices and a central channel for the transport of ammonium.	INTRO
+4	14	structures	evidence	All structures show the transporters in open conformations.	INTRO
+24	36	transporters	protein_type	All structures show the transporters in open conformations.	INTRO
+40	44	open	protein_state	All structures show the transporters in open conformations.	INTRO
+48	55	ammonia	chemical	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+117	133	Amt/Mep proteins	protein_type	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+146	152	active	protein_state	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+154	179	electrogenic transporters	protein_type	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+190	194	NH4+	chemical	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+208	211	NH3	chemical	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+212	214	H+	chemical	Where earlier studies favoured the transport of ammonia gas, recent data and theoretical considerations suggest that Amt/Mep proteins are instead active, electrogenic transporters of either NH4+ (uniport) or NH3/H+ (symport).	INTRO
+2	18	highly conserved	protein_state	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+27	34	channel	site	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+42	51	histidine	residue_name	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+72	86	twin-His motif	structure_element	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+128	131	NH3	chemical	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+150	157	channel	site	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+165	168	NH3	chemical	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+169	171	H+	chemical	A highly conserved pair of channel-lining histidine residues dubbed the twin-His motif may serve as a proton relay system while NH3 moves through the channel during NH3/H+ symport.	INTRO
+0	8	Ammonium	chemical	Ammonium transport is tightly regulated.	INTRO
+3	10	animals	taxonomy_domain	In animals, this is due to toxicity of elevated intracellular ammonium levels, whereas for microorganisms ammonium is a preferred nitrogen source.	INTRO
+62	70	ammonium	chemical	In animals, this is due to toxicity of elevated intracellular ammonium levels, whereas for microorganisms ammonium is a preferred nitrogen source.	INTRO
+91	105	microorganisms	taxonomy_domain	In animals, this is due to toxicity of elevated intracellular ammonium levels, whereas for microorganisms ammonium is a preferred nitrogen source.	INTRO
+106	114	ammonium	chemical	In animals, this is due to toxicity of elevated intracellular ammonium levels, whereas for microorganisms ammonium is a preferred nitrogen source.	INTRO
+3	11	bacteria	taxonomy_domain	In bacteria, amt genes are present in an operon with glnK, encoding a PII-like signal transduction class protein.	INTRO
+13	16	amt	gene	In bacteria, amt genes are present in an operon with glnK, encoding a PII-like signal transduction class protein.	INTRO
+53	57	glnK	gene	In bacteria, amt genes are present in an operon with glnK, encoding a PII-like signal transduction class protein.	INTRO
+70	112	PII-like signal transduction class protein	protein_type	In bacteria, amt genes are present in an operon with glnK, encoding a PII-like signal transduction class protein.	INTRO
+22	34	Amt proteins	protein_type	By binding tightly to Amt proteins without inducing a conformational change in the transporter, GlnK sterically blocks ammonium conductance when nitrogen levels are sufficient.	INTRO
+83	94	transporter	protein_type	By binding tightly to Amt proteins without inducing a conformational change in the transporter, GlnK sterically blocks ammonium conductance when nitrogen levels are sufficient.	INTRO
+96	100	GlnK	protein_type	By binding tightly to Amt proteins without inducing a conformational change in the transporter, GlnK sterically blocks ammonium conductance when nitrogen levels are sufficient.	INTRO
+119	127	ammonium	chemical	By binding tightly to Amt proteins without inducing a conformational change in the transporter, GlnK sterically blocks ammonium conductance when nitrogen levels are sufficient.	INTRO
+20	28	nitrogen	chemical	Under conditions of nitrogen limitation, GlnK becomes uridylated, blocking its ability to bind and inhibit Amt proteins.	INTRO
+41	45	GlnK	protein_type	Under conditions of nitrogen limitation, GlnK becomes uridylated, blocking its ability to bind and inhibit Amt proteins.	INTRO
+54	64	uridylated	protein_state	Under conditions of nitrogen limitation, GlnK becomes uridylated, blocking its ability to bind and inhibit Amt proteins.	INTRO
+107	119	Amt proteins	protein_type	Under conditions of nitrogen limitation, GlnK becomes uridylated, blocking its ability to bind and inhibit Amt proteins.	INTRO
+13	23	eukaryotes	taxonomy_domain	Importantly, eukaryotes do not have GlnK orthologues and have a different mechanism for regulation of ammonium transport activity.	INTRO
+36	40	GlnK	protein_type	Importantly, eukaryotes do not have GlnK orthologues and have a different mechanism for regulation of ammonium transport activity.	INTRO
+102	110	ammonium	chemical	Importantly, eukaryotes do not have GlnK orthologues and have a different mechanism for regulation of ammonium transport activity.	INTRO
+3	9	plants	taxonomy_domain	In plants, transporter phosphorylation and dephosphorylation are known to regulate activity.	INTRO
+11	22	transporter	protein_type	In plants, transporter phosphorylation and dephosphorylation are known to regulate activity.	INTRO
+23	38	phosphorylation	ptm	In plants, transporter phosphorylation and dephosphorylation are known to regulate activity.	INTRO
+43	60	dephosphorylation	ptm	In plants, transporter phosphorylation and dephosphorylation are known to regulate activity.	INTRO
+3	16	S. cerevisiae	species	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+18	33	phosphorylation	ptm	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+37	43	Ser457	residue_name_number	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+55	72	C-terminal region	structure_element	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+74	77	CTR	structure_element	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+127	131	Mep2	protein_type	In S. cerevisiae, phosphorylation of Ser457 within the C-terminal region (CTR) in the cytoplasm was recently proposed to cause Mep2 opening, possibly via inducing a conformational change.	INTRO
+30	34	Mep2	protein_type	To elucidate the mechanism of Mep2 transport regulation, we present here X-ray crystal structures of the Mep2 transceptors from S. cerevisiae and C. albicans.	INTRO
+73	97	X-ray crystal structures	evidence	To elucidate the mechanism of Mep2 transport regulation, we present here X-ray crystal structures of the Mep2 transceptors from S. cerevisiae and C. albicans.	INTRO
+105	122	Mep2 transceptors	protein_type	To elucidate the mechanism of Mep2 transport regulation, we present here X-ray crystal structures of the Mep2 transceptors from S. cerevisiae and C. albicans.	INTRO
+128	141	S. cerevisiae	species	To elucidate the mechanism of Mep2 transport regulation, we present here X-ray crystal structures of the Mep2 transceptors from S. cerevisiae and C. albicans.	INTRO
+146	157	C. albicans	species	To elucidate the mechanism of Mep2 transport regulation, we present here X-ray crystal structures of the Mep2 transceptors from S. cerevisiae and C. albicans.	INTRO
+4	14	structures	evidence	The structures are similar to each other but show considerable differences to all other ammonium transporter structures.	INTRO
+88	108	ammonium transporter	protein_type	The structures are similar to each other but show considerable differences to all other ammonium transporter structures.	INTRO
+109	119	structures	evidence	The structures are similar to each other but show considerable differences to all other ammonium transporter structures.	INTRO
+50	63	Mep2 proteins	protein_type	The most striking difference is the fact that the Mep2 proteins have closed conformations.	INTRO
+69	75	closed	protein_state	The most striking difference is the fact that the Mep2 proteins have closed conformations.	INTRO
+13	33	phosphorylation site	site	The putative phosphorylation site is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	INTRO
+37	55	solvent accessible	protein_state	The putative phosphorylation site is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	INTRO
+73	98	negatively charged pocket	site	The putative phosphorylation site is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	INTRO
+119	131	channel exit	site	The putative phosphorylation site is solvent accessible and located in a negatively charged pocket ∼30 Å away from the channel exit.	INTRO
+4	12	channels	site	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+16	49	phosphorylation-mimicking mutants	protein_state	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+53	64	C. albicans	species	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+65	69	Mep2	protein	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+80	86	closed	protein_state	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+134	143	conserved	protein_state	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+156	159	CTR	structure_element	The channels of phosphorylation-mimicking mutants of C. albicans Mep2 are still closed but show large conformational changes within a conserved part of the CTR.	INTRO
+16	25	structure	evidence	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+42	54	Mep2 variant	mutant	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+55	62	lacking	protein_state	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+67	74	segment	structure_element	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+90	110	phosphorylation site	site	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+203	213	eukaryotic	taxonomy_domain	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+214	222	ammonium	chemical	Together with a structure of a C-terminal Mep2 variant lacking the segment containing the phosphorylation site, the results allow us to propose a structural model for phosphorylation-based regulation of eukaryotic ammonium transport.	INTRO
+24	28	Mep2	protein_type	General architecture of Mep2 ammonium transceptors	RESULTS
+29	50	ammonium transceptors	protein_type	General architecture of Mep2 ammonium transceptors	RESULTS
+4	8	Mep2	protein	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+20	33	S. cerevisiae	species	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+35	41	ScMep2	protein	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+47	60	overexpressed	experimental_method	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+64	77	S. cerevisiae	species	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+103	126	structure determination	experimental_method	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+130	151	X-ray crystallography	experimental_method	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+186	207	molecular replacement	experimental_method	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+209	211	MR	experimental_method	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+222	237	archaebacterial	taxonomy_domain	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+238	243	Amt-1	protein	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+244	253	structure	evidence	The Mep2 protein of S. cerevisiae (ScMep2) was overexpressed in S. cerevisiae in high yields, enabling structure determination by X-ray crystallography using data to 3.2 Å resolution by molecular replacement (MR) with the archaebacterial Amt-1 structure (see Methods section).	RESULTS
+40	49	structure	evidence	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+89	95	ScMep2	protein	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+120	146	structure–function studies	experimental_method	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+162	168	fungal	taxonomy_domain	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+169	173	Mep2	protein_type	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+204	234	overexpressed and screened for	experimental_method	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+255	263	crystals	evidence	Given that the modest resolution of the structure and the limited detergent stability of ScMep2 would likely complicate structure–function studies, several other fungal Mep2 orthologues were subsequently overexpressed and screened for diffraction-quality crystals.	RESULTS
+10	14	Mep2	protein	Of these, Mep2 from C. albicans (CaMep2) showed superior stability in relatively harsh detergents such as nonyl-glucoside, allowing structure determination in two different crystal forms to high resolution (up to 1.5 Å).	RESULTS
+20	31	C. albicans	species	Of these, Mep2 from C. albicans (CaMep2) showed superior stability in relatively harsh detergents such as nonyl-glucoside, allowing structure determination in two different crystal forms to high resolution (up to 1.5 Å).	RESULTS
+33	39	CaMep2	protein	Of these, Mep2 from C. albicans (CaMep2) showed superior stability in relatively harsh detergents such as nonyl-glucoside, allowing structure determination in two different crystal forms to high resolution (up to 1.5 Å).	RESULTS
+132	155	structure determination	experimental_method	Of these, Mep2 from C. albicans (CaMep2) showed superior stability in relatively harsh detergents such as nonyl-glucoside, allowing structure determination in two different crystal forms to high resolution (up to 1.5 Å).	RESULTS
+173	186	crystal forms	evidence	Of these, Mep2 from C. albicans (CaMep2) showed superior stability in relatively harsh detergents such as nonyl-glucoside, allowing structure determination in two different crystal forms to high resolution (up to 1.5 Å).	RESULTS
+67	73	CaMep2	protein	Despite different crystal packing (Supplementary Table 1), the two CaMep2 structures are identical to each other and very similar to ScMep2 (Cα r.m.s.d.	RESULTS
+74	84	structures	evidence	Despite different crystal packing (Supplementary Table 1), the two CaMep2 structures are identical to each other and very similar to ScMep2 (Cα r.m.s.d.	RESULTS
+133	139	ScMep2	protein	Despite different crystal packing (Supplementary Table 1), the two CaMep2 structures are identical to each other and very similar to ScMep2 (Cα r.m.s.d.	RESULTS
+144	152	r.m.s.d.	evidence	Despite different crystal packing (Supplementary Table 1), the two CaMep2 structures are identical to each other and very similar to ScMep2 (Cα r.m.s.d.	RESULTS
+1	27	root mean square deviation	evidence	(root mean square deviation)=0.7 Å for 434 residues), with the main differences confined to the N terminus and the CTR (Fig. 1).	RESULTS
+115	118	CTR	structure_element	(root mean square deviation)=0.7 Å for 434 residues), with the main differences confined to the N terminus and the CTR (Fig. 1).	RESULTS
+0	16	Electron density	evidence	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+100	102	43	residue_range	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+104	110	ScMep2	protein	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+116	118	25	residue_range	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+129	135	CaMep2	protein	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+148	164	poorly conserved	protein_state	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+180	190	disordered	protein_state	Electron density is visible for the entire polypeptide chains, with the exception of the C-terminal 43 (ScMep2) and 25 residues (CaMep2), which are poorly conserved and presumably disordered.	RESULTS
+5	18	Mep2 proteins	protein_type	Both Mep2 proteins show the archetypal trimeric assemblies in which each monomer consists of 11 TM helices surrounding a central pore.	RESULTS
+39	47	trimeric	oligomeric_state	Both Mep2 proteins show the archetypal trimeric assemblies in which each monomer consists of 11 TM helices surrounding a central pore.	RESULTS
+73	80	monomer	oligomeric_state	Both Mep2 proteins show the archetypal trimeric assemblies in which each monomer consists of 11 TM helices surrounding a central pore.	RESULTS
+96	106	TM helices	structure_element	Both Mep2 proteins show the archetypal trimeric assemblies in which each monomer consists of 11 TM helices surrounding a central pore.	RESULTS
+121	133	central pore	structure_element	Both Mep2 proteins show the archetypal trimeric assemblies in which each monomer consists of 11 TM helices surrounding a central pore.	RESULTS
+56	77	ammonium binding site	site	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+83	91	Phe gate	site	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+100	114	twin-His motif	structure_element	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+126	145	hydrophobic channel	site	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+191	200	bacterial	taxonomy_domain	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+201	213	transporters	protein_type	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+218	222	RhCG	protein	Important functional features such as the extracellular ammonium binding site, the Phe gate and the twin-His motif within the hydrophobic channel are all very similar to those present in the bacterial transporters and RhCG.	RESULTS
+65	71	CaMep2	protein	In the remainder of the manuscript, we will specifically discuss CaMep2 due to the superior resolution of the structure.	RESULTS
+110	119	structure	evidence	In the remainder of the manuscript, we will specifically discuss CaMep2 due to the superior resolution of the structure.	RESULTS
+64	70	ScMep2	protein	Unless specifically stated, the drawn conclusions also apply to ScMep2.	RESULTS
+34	38	Mep2	protein	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+65	76	prokaryotic	taxonomy_domain	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+77	89	transporters	protein_type	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+94	102	r.m.s.d.	evidence	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+108	113	Amt-1	protein	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+190	209	intracellular loops	structure_element	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+211	215	ICLs	structure_element	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+217	221	ICL1	structure_element	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+226	230	ICL3	structure_element	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+240	243	CTR	structure_element	While the overall architecture of Mep2 is similar to that of the prokaryotic transporters (Cα r.m.s.d. with Amt-1=1.4 Å for 361 residues), there are large differences within the N terminus, intracellular loops (ICLs) ICL1 and ICL3, and the CTR.	RESULTS
+21	34	Mep2 proteins	protein_type	The N termini of the Mep2 proteins are ∼20–25 residues longer compared with their bacterial counterparts (Figs 1 and 2), substantially increasing the size of the extracellular domain.	RESULTS
+40	45	20–25	residue_range	The N termini of the Mep2 proteins are ∼20–25 residues longer compared with their bacterial counterparts (Figs 1 and 2), substantially increasing the size of the extracellular domain.	RESULTS
+82	91	bacterial	taxonomy_domain	The N termini of the Mep2 proteins are ∼20–25 residues longer compared with their bacterial counterparts (Figs 1 and 2), substantially increasing the size of the extracellular domain.	RESULTS
+162	182	extracellular domain	structure_element	The N termini of the Mep2 proteins are ∼20–25 residues longer compared with their bacterial counterparts (Figs 1 and 2), substantially increasing the size of the extracellular domain.	RESULTS
+32	39	monomer	oligomeric_state	Moreover, the N terminus of one monomer interacts with the extended extracellular loop ECL5 of a neighbouring monomer.	RESULTS
+68	86	extracellular loop	structure_element	Moreover, the N terminus of one monomer interacts with the extended extracellular loop ECL5 of a neighbouring monomer.	RESULTS
+87	91	ECL5	structure_element	Moreover, the N terminus of one monomer interacts with the extended extracellular loop ECL5 of a neighbouring monomer.	RESULTS
+110	117	monomer	oligomeric_state	Moreover, the N terminus of one monomer interacts with the extended extracellular loop ECL5 of a neighbouring monomer.	RESULTS
+55	74	extracellular loops	structure_element	Together with additional, smaller differences in other extracellular loops, these changes generate a distinct vestibule leading to the ammonium binding site that is much more pronounced than in the bacterial proteins.	RESULTS
+110	119	vestibule	structure_element	Together with additional, smaller differences in other extracellular loops, these changes generate a distinct vestibule leading to the ammonium binding site that is much more pronounced than in the bacterial proteins.	RESULTS
+135	156	ammonium binding site	site	Together with additional, smaller differences in other extracellular loops, these changes generate a distinct vestibule leading to the ammonium binding site that is much more pronounced than in the bacterial proteins.	RESULTS
+198	207	bacterial	taxonomy_domain	Together with additional, smaller differences in other extracellular loops, these changes generate a distinct vestibule leading to the ammonium binding site that is much more pronounced than in the bacterial proteins.	RESULTS
+15	24	vestibule	structure_element	The N-terminal vestibule and the resulting inter-monomer interactions likely increase the stability of the Mep2 trimer, in support of data for plant AMT proteins.	RESULTS
+107	111	Mep2	protein	The N-terminal vestibule and the resulting inter-monomer interactions likely increase the stability of the Mep2 trimer, in support of data for plant AMT proteins.	RESULTS
+112	118	trimer	oligomeric_state	The N-terminal vestibule and the resulting inter-monomer interactions likely increase the stability of the Mep2 trimer, in support of data for plant AMT proteins.	RESULTS
+143	148	plant	taxonomy_domain	The N-terminal vestibule and the resulting inter-monomer interactions likely increase the stability of the Mep2 trimer, in support of data for plant AMT proteins.	RESULTS
+149	161	AMT proteins	protein_type	The N-terminal vestibule and the resulting inter-monomer interactions likely increase the stability of the Mep2 trimer, in support of data for plant AMT proteins.	RESULTS
+34	49	deletion mutant	protein_state	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+51	56	2-27Δ	mutant	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+75	84	wild-type	protein_state	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+86	88	WT	protein_state	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+90	94	Mep2	protein	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+106	114	ammonium	chemical	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+194	198	Mep2	protein	However, given that an N-terminal deletion mutant (2-27Δ) grows as well as wild-type (WT) Mep2 on minimal ammonium medium (Fig. 3 and Supplementary Fig. 1), the importance of the N terminus for Mep2 activity is not clear.	RESULTS
+0	4	Mep2	protein	Mep2 channels are closed by a two-tier channel block	RESULTS
+5	13	channels	site	Mep2 channels are closed by a two-tier channel block	RESULTS
+18	24	closed	protein_state	Mep2 channels are closed by a two-tier channel block	RESULTS
+39	52	channel block	structure_element	Mep2 channels are closed by a two-tier channel block	RESULTS
+36	40	Mep2	protein	The largest differences between the Mep2 structures and the other known ammonium transporter structures are located on the intracellular side of the membrane.	RESULTS
+41	51	structures	evidence	The largest differences between the Mep2 structures and the other known ammonium transporter structures are located on the intracellular side of the membrane.	RESULTS
+72	92	ammonium transporter	protein_type	The largest differences between the Mep2 structures and the other known ammonium transporter structures are located on the intracellular side of the membrane.	RESULTS
+93	103	structures	evidence	The largest differences between the Mep2 structures and the other known ammonium transporter structures are located on the intracellular side of the membrane.	RESULTS
+23	27	Mep2	protein	In the vicinity of the Mep2 channel exit, the cytoplasmic end of TM2 has unwound, generating a longer ICL1 even though there are no insertions in this region compared to the bacterial proteins (Figs 2 and 4).	RESULTS
+28	40	channel exit	site	In the vicinity of the Mep2 channel exit, the cytoplasmic end of TM2 has unwound, generating a longer ICL1 even though there are no insertions in this region compared to the bacterial proteins (Figs 2 and 4).	RESULTS
+65	68	TM2	structure_element	In the vicinity of the Mep2 channel exit, the cytoplasmic end of TM2 has unwound, generating a longer ICL1 even though there are no insertions in this region compared to the bacterial proteins (Figs 2 and 4).	RESULTS
+102	106	ICL1	structure_element	In the vicinity of the Mep2 channel exit, the cytoplasmic end of TM2 has unwound, generating a longer ICL1 even though there are no insertions in this region compared to the bacterial proteins (Figs 2 and 4).	RESULTS
+174	183	bacterial	taxonomy_domain	In the vicinity of the Mep2 channel exit, the cytoplasmic end of TM2 has unwound, generating a longer ICL1 even though there are no insertions in this region compared to the bacterial proteins (Figs 2 and 4).	RESULTS
+0	4	ICL1	structure_element	ICL1 has also moved inwards relative to its position in the bacterial Amts.	RESULTS
+60	69	bacterial	taxonomy_domain	ICL1 has also moved inwards relative to its position in the bacterial Amts.	RESULTS
+70	74	Amts	protein_type	ICL1 has also moved inwards relative to its position in the bacterial Amts.	RESULTS
+61	65	ICL1	structure_element	The largest backbone movements of equivalent residues within ICL1 are ∼10 Å, markedly affecting the conserved basic RxK motif (Fig. 4).	RESULTS
+100	109	conserved	protein_state	The largest backbone movements of equivalent residues within ICL1 are ∼10 Å, markedly affecting the conserved basic RxK motif (Fig. 4).	RESULTS
+110	115	basic	protein_state	The largest backbone movements of equivalent residues within ICL1 are ∼10 Å, markedly affecting the conserved basic RxK motif (Fig. 4).	RESULTS
+116	125	RxK motif	structure_element	The largest backbone movements of equivalent residues within ICL1 are ∼10 Å, markedly affecting the conserved basic RxK motif (Fig. 4).	RESULTS
+18	23	Arg54	residue_name_number	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+60	65	Amt-1	protein	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+119	124	Lys55	residue_name_number	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+167	172	Lys56	residue_name_number	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+180	185	basic	protein_state	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+186	191	motif	structure_element	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+231	235	Mep2	protein	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+236	246	structures	evidence	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+283	288	Amt-1	protein	The head group of Arg54 has moved ∼11 Å relative to that in Amt-1, whereas the shift of the head group of the variable Lys55 residue is almost 20 Å. The side chain of Lys56 in the basic motif points in an opposite direction in the Mep2 structures compared with that of, for example, Amt-1 (Fig. 4).	RESULTS
+28	37	RxK motif	structure_element	In addition to changing the RxK motif, the movement of ICL1 has another, crucial functional consequence.	RESULTS
+55	59	ICL1	structure_element	In addition to changing the RxK motif, the movement of ICL1 has another, crucial functional consequence.	RESULTS
+25	28	TM1	structure_element	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+67	87	relatively conserved	protein_state	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+88	93	Tyr49	residue_name_number	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+95	100	Tyr53	residue_name_number	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+104	110	ScMep2	protein	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+174	194	absolutely conserved	protein_state	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+195	201	His342	residue_name_number	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+209	223	twin-His motif	structure_element	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+225	231	His348	residue_name_number	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+235	241	ScMep2	protein	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+256	263	channel	site	At the C-terminal end of TM1, the side-chain hydroxyl group of the relatively conserved Tyr49 (Tyr53 in ScMep2) makes a strong hydrogen bond with the ɛ2 nitrogen atom of the absolutely conserved His342 of the twin-His motif (His348 in ScMep2), closing the channel (Figs 4 and 5).	RESULTS
+3	12	bacterial	taxonomy_domain	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+13	25	Amt proteins	protein_type	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+32	35	Tyr	residue_name	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+113	116	TM1	structure_element	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+130	137	channel	site	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+138	142	open	protein_state	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+151	160	histidine	residue_name	In bacterial Amt proteins, this Tyr side chain is rotated ∼4 Å away as a result of the different conformation of TM1, leaving the channel open and the histidine available for its putative role in substrate transport (Supplementary Fig. 2).	RESULTS
+14	18	ICL1	structure_element	Compared with ICL1, the backbone conformational changes observed for the neighbouring ICL2 are smaller, but large shifts are nevertheless observed for the conserved residues Glu140 and Arg141 (Fig. 4).	RESULTS
+86	90	ICL2	structure_element	Compared with ICL1, the backbone conformational changes observed for the neighbouring ICL2 are smaller, but large shifts are nevertheless observed for the conserved residues Glu140 and Arg141 (Fig. 4).	RESULTS
+155	164	conserved	protein_state	Compared with ICL1, the backbone conformational changes observed for the neighbouring ICL2 are smaller, but large shifts are nevertheless observed for the conserved residues Glu140 and Arg141 (Fig. 4).	RESULTS
+174	180	Glu140	residue_name_number	Compared with ICL1, the backbone conformational changes observed for the neighbouring ICL2 are smaller, but large shifts are nevertheless observed for the conserved residues Glu140 and Arg141 (Fig. 4).	RESULTS
+185	191	Arg141	residue_name_number	Compared with ICL1, the backbone conformational changes observed for the neighbouring ICL2 are smaller, but large shifts are nevertheless observed for the conserved residues Glu140 and Arg141 (Fig. 4).	RESULTS
+23	27	ICL3	structure_element	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+40	65	pseudo-symmetrical halves	structure_element	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+67	72	TM1-5	structure_element	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+77	83	TM6-10	structure_element	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+92	103	transporter	protein_type	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+180	187	channel	site	Finally, the important ICL3 linking the pseudo-symmetrical halves (TM1-5 and TM6-10) of the transporter is also shifted up to ∼10 Å and forms an additional barrier that closes the channel on the cytoplasmic side (Fig. 5).	RESULTS
+14	27	channel block	structure_element	This two-tier channel block likely ensures that very little ammonium transport will take place under nitrogen-sufficient conditions.	RESULTS
+60	68	ammonium	chemical	This two-tier channel block likely ensures that very little ammonium transport will take place under nitrogen-sufficient conditions.	RESULTS
+101	109	nitrogen	chemical	This two-tier channel block likely ensures that very little ammonium transport will take place under nitrogen-sufficient conditions.	RESULTS
+4	10	closed	protein_state	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+24	31	channel	site	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+55	65	no density	evidence	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+93	101	ammonium	chemical	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+106	111	water	chemical	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+157	161	Mep2	protein	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+162	169	channel	site	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+183	197	twin-His motif	structure_element	The closed state of the channel might also explain why no density, which could correspond to ammonium (or water), is observed in the hydrophobic part of the Mep2 channel close to the twin-His motif.	RESULTS
+37	43	ScMep2	protein	Significantly, this is also true for ScMep2, which was crystallized in the presence of 0.2 M ammonium ions (see Methods section).	RESULTS
+55	67	crystallized	experimental_method	Significantly, this is also true for ScMep2, which was crystallized in the presence of 0.2 M ammonium ions (see Methods section).	RESULTS
+93	101	ammonium	chemical	Significantly, this is also true for ScMep2, which was crystallized in the presence of 0.2 M ammonium ions (see Methods section).	RESULTS
+20	24	Mep2	protein	The final region in Mep2 that shows large differences compared with the bacterial transporters is the CTR.	RESULTS
+72	81	bacterial	taxonomy_domain	The final region in Mep2 that shows large differences compared with the bacterial transporters is the CTR.	RESULTS
+82	94	transporters	protein_type	The final region in Mep2 that shows large differences compared with the bacterial transporters is the CTR.	RESULTS
+102	105	CTR	structure_element	The final region in Mep2 that shows large differences compared with the bacterial transporters is the CTR.	RESULTS
+3	7	Mep2	protein	In Mep2, the CTR has moved away and makes relatively few contacts with the main body of the transporter, generating a more elongated protein (Figs 1 and 4).	RESULTS
+13	16	CTR	structure_element	In Mep2, the CTR has moved away and makes relatively few contacts with the main body of the transporter, generating a more elongated protein (Figs 1 and 4).	RESULTS
+75	84	main body	structure_element	In Mep2, the CTR has moved away and makes relatively few contacts with the main body of the transporter, generating a more elongated protein (Figs 1 and 4).	RESULTS
+92	103	transporter	protein_type	In Mep2, the CTR has moved away and makes relatively few contacts with the main body of the transporter, generating a more elongated protein (Figs 1 and 4).	RESULTS
+123	132	elongated	protein_state	In Mep2, the CTR has moved away and makes relatively few contacts with the main body of the transporter, generating a more elongated protein (Figs 1 and 4).	RESULTS
+20	30	structures	evidence	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+34	43	bacterial	taxonomy_domain	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+58	61	CTR	structure_element	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+89	104	N-terminal half	structure_element	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+112	124	transporters	protein_type	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+143	148	TM1-5	structure_element	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+171	178	compact	protein_state	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+179	188	structure	evidence	By contrast, in the structures of bacterial proteins, the CTR is docked tightly onto the N-terminal half of the transporters (corresponding to TM1-5), resulting in a more compact structure.	RESULTS
+49	70	universally conserved	protein_state	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+91	94	CTR	structure_element	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+105	111	Arg415	residue_name_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+112	115	370	residue_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+118	124	Glu421	residue_name_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+125	128	376	residue_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+131	137	Gly424	residue_name_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+138	141	379	residue_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+144	150	Asp426	residue_name_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+151	154	381	residue_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+160	167	Tyr 435	residue_name_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+168	171	390	residue_number	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+176	182	CaMep2	protein	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+183	188	Amt-1	protein	This is illustrated by the positions of the five universally conserved residues within the CTR, that is, Arg415(370), Glu421(376), Gly424(379), Asp426(381) and Tyr 435(390) in CaMep2(Amt-1) (Fig. 2).	RESULTS
+36	50	‘ExxGxD' motif	structure_element	These residues include those of the ‘ExxGxD' motif, which when mutated generate inactive transporters.	RESULTS
+63	70	mutated	experimental_method	These residues include those of the ‘ExxGxD' motif, which when mutated generate inactive transporters.	RESULTS
+80	88	inactive	protein_state	These residues include those of the ‘ExxGxD' motif, which when mutated generate inactive transporters.	RESULTS
+89	101	transporters	protein_type	These residues include those of the ‘ExxGxD' motif, which when mutated generate inactive transporters.	RESULTS
+3	8	Amt-1	protein	In Amt-1 and other bacterial ammonium transporters, these CTR residues interact with residues within the N-terminal half of the protein.	RESULTS
+19	28	bacterial	taxonomy_domain	In Amt-1 and other bacterial ammonium transporters, these CTR residues interact with residues within the N-terminal half of the protein.	RESULTS
+29	50	ammonium transporters	protein_type	In Amt-1 and other bacterial ammonium transporters, these CTR residues interact with residues within the N-terminal half of the protein.	RESULTS
+58	61	CTR	structure_element	In Amt-1 and other bacterial ammonium transporters, these CTR residues interact with residues within the N-terminal half of the protein.	RESULTS
+105	120	N-terminal half	structure_element	In Amt-1 and other bacterial ammonium transporters, these CTR residues interact with residues within the N-terminal half of the protein.	RESULTS
+17	23	Tyr390	residue_name_number	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+36	41	Amt-1	protein	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+88	97	conserved	protein_state	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+98	104	His185	residue_name_number	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+130	134	loop	structure_element	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+135	139	ICL3	structure_element	On one side, the Tyr390 hydroxyl in Amt-1 is hydrogen bonded with the side chain of the conserved His185 at the C-terminal end of loop ICL3.	RESULTS
+20	24	ICL3	structure_element	At the other end of ICL3, the backbone carbonyl groups of Gly172 and Lys173 are hydrogen bonded to the side chain of Arg370.	RESULTS
+58	64	Gly172	residue_name_number	At the other end of ICL3, the backbone carbonyl groups of Gly172 and Lys173 are hydrogen bonded to the side chain of Arg370.	RESULTS
+69	75	Lys173	residue_name_number	At the other end of ICL3, the backbone carbonyl groups of Gly172 and Lys173 are hydrogen bonded to the side chain of Arg370.	RESULTS
+117	123	Arg370	residue_name_number	At the other end of ICL3, the backbone carbonyl groups of Gly172 and Lys173 are hydrogen bonded to the side chain of Arg370.	RESULTS
+31	39	modelled	experimental_method	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+47	53	active	protein_state	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+55	73	non-phosphorylated	protein_state	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+74	79	plant	taxonomy_domain	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+80	89	AtAmt-1;1	protein	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+90	99	structure	evidence	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+114	118	Y467	residue_name_number	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+119	123	H239	residue_name_number	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+128	132	D458	residue_name_number	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+133	136	K71	residue_name_number	Similar interactions were also modelled in the active, non-phosphorylated plant AtAmt-1;1 structure (for example, Y467-H239 and D458-K71).	RESULTS
+45	48	CTR	structure_element	The result of these interactions is that the CTR ‘hugs' the N-terminal half of the transporters (Fig. 4).	RESULTS
+60	75	N-terminal half	structure_element	The result of these interactions is that the CTR ‘hugs' the N-terminal half of the transporters (Fig. 4).	RESULTS
+83	95	transporters	protein_type	The result of these interactions is that the CTR ‘hugs' the N-terminal half of the transporters (Fig. 4).	RESULTS
+19	25	Asp381	residue_name_number	Also noteworthy is Asp381, the side chain of which interacts strongly with the positive dipole on the N-terminal end of TM2.	RESULTS
+120	123	TM2	structure_element	Also noteworthy is Asp381, the side chain of which interacts strongly with the positive dipole on the N-terminal end of TM2.	RESULTS
+93	97	open	protein_state	This interaction in the centre of the protein may be particularly important to stabilize the open conformations of ammonium transporters.	RESULTS
+115	136	ammonium transporters	protein_type	This interaction in the centre of the protein may be particularly important to stabilize the open conformations of ammonium transporters.	RESULTS
+7	11	Mep2	protein	In the Mep2 structures, none of the interactions mentioned above are present.	RESULTS
+12	22	structures	evidence	In the Mep2 structures, none of the interactions mentioned above are present.	RESULTS
+0	27	Phosphorylation target site	site	Phosphorylation target site is at the periphery of Mep2	RESULTS
+51	55	Mep2	protein	Phosphorylation target site is at the periphery of Mep2	RESULTS
+51	57	Ser457	residue_name_number	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+61	67	ScMep2	protein	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+86	92	Ser453	residue_name_number	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+96	102	CaMep2	protein	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+107	121	phosphorylated	protein_state	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+129	150	TORC1 effector kinase	protein_type	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+151	155	Npr1	protein	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+162	170	nitrogen	chemical	Recently Boeckstaens et al. provided evidence that Ser457 in ScMep2 (corresponding to Ser453 in CaMep2) is phosphorylated by the TORC1 effector kinase Npr1 under nitrogen-limiting conditions.	RESULTS
+7	17	absence of	protein_state	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+18	22	Npr1	protein	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+24	39	plasmid-encoded	experimental_method	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+40	42	WT	protein_state	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+43	47	Mep2	protein	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+53	66	S. cerevisiae	species	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+67	74	mep1-3Δ	mutant	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+83	94	triple mepΔ	mutant	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+143	151	ammonium	chemical	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+173	184	transporter	protein_type	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+188	196	inactive	protein_state	In the absence of Npr1, plasmid-encoded WT Mep2 in a S. cerevisiae mep1-3Δ strain (triple mepΔ) does not allow growth on low concentrations of ammonium, suggesting that the transporter is inactive (Fig. 3 and Supplementary Fig. 1).	RESULTS
+16	41	phosphorylation-mimicking	protein_state	Conversely, the phosphorylation-mimicking S457D variant is active both in the triple mepΔ background and in a triple mepΔ npr1Δ strain (Fig. 3).	RESULTS
+42	47	S457D	mutant	Conversely, the phosphorylation-mimicking S457D variant is active both in the triple mepΔ background and in a triple mepΔ npr1Δ strain (Fig. 3).	RESULTS
+59	65	active	protein_state	Conversely, the phosphorylation-mimicking S457D variant is active both in the triple mepΔ background and in a triple mepΔ npr1Δ strain (Fig. 3).	RESULTS
+78	89	triple mepΔ	mutant	Conversely, the phosphorylation-mimicking S457D variant is active both in the triple mepΔ background and in a triple mepΔ npr1Δ strain (Fig. 3).	RESULTS
+110	127	triple mepΔ npr1Δ	mutant	Conversely, the phosphorylation-mimicking S457D variant is active both in the triple mepΔ background and in a triple mepΔ npr1Δ strain (Fig. 3).	RESULTS
+0	8	Mutation	experimental_method	Mutation of other potential phosphorylation sites in the CTR did not support growth in the npr1Δ background.	RESULTS
+28	49	phosphorylation sites	site	Mutation of other potential phosphorylation sites in the CTR did not support growth in the npr1Δ background.	RESULTS
+57	60	CTR	structure_element	Mutation of other potential phosphorylation sites in the CTR did not support growth in the npr1Δ background.	RESULTS
+91	96	npr1Δ	mutant	Mutation of other potential phosphorylation sites in the CTR did not support growth in the npr1Δ background.	RESULTS
+38	53	phosphorylation	ptm	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+57	63	Ser457	residue_name_number	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+57	63	Ser457	residue_name_number	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+74	78	Mep2	protein	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+79	86	channel	site	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+96	104	ammonium	chemical	Collectively, these data suggest that phosphorylation of Ser457 opens the Mep2 channel to allow ammonium uptake.	RESULTS
+0	6	Ser457	residue_name_number	Ser457 is located in a part of the CTR that is conserved in a subgroup of Mep2 proteins, but which is not present in bacterial proteins (Fig. 2).	RESULTS
+35	38	CTR	structure_element	Ser457 is located in a part of the CTR that is conserved in a subgroup of Mep2 proteins, but which is not present in bacterial proteins (Fig. 2).	RESULTS
+47	56	conserved	protein_state	Ser457 is located in a part of the CTR that is conserved in a subgroup of Mep2 proteins, but which is not present in bacterial proteins (Fig. 2).	RESULTS
+74	87	Mep2 proteins	protein_type	Ser457 is located in a part of the CTR that is conserved in a subgroup of Mep2 proteins, but which is not present in bacterial proteins (Fig. 2).	RESULTS
+117	126	bacterial	taxonomy_domain	Ser457 is located in a part of the CTR that is conserved in a subgroup of Mep2 proteins, but which is not present in bacterial proteins (Fig. 2).	RESULTS
+5	12	segment	structure_element	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+23	30	450–457	residue_range	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+34	40	ScMep2	protein	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+45	52	446–453	residue_range	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+56	62	CaMep2	protein	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+78	104	autoinhibitory (AI) region	structure_element	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+132	139	removal	experimental_method	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+153	159	active	protein_state	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+160	171	transporter	protein_type	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+179	189	absence of	protein_state	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+190	194	Npr1	protein	This segment (residues 450–457 in ScMep2 and 446–453 in CaMep2) was dubbed an autoinhibitory (AI) region based on the fact that its removal generates an active transporter in the absence of Npr1 (Fig. 3).	RESULTS
+13	22	AI region	structure_element	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+31	35	Npr1	protein	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+36	56	phosphorylation site	site	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+70	80	structures	evidence	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+111	120	AI region	structure_element	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+145	148	CTR	structure_element	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+191	197	trimer	oligomeric_state	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+219	228	bacterial	taxonomy_domain	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+229	239	structures	evidence	Where is the AI region and the Npr1 phosphorylation site located? Our structures reveal that surprisingly, the AI region is folded back onto the CTR and is not located near the centre of the trimer as expected from the bacterial structures (Fig. 4).	RESULTS
+4	13	AI region	structure_element	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+52	55	TM2	structure_element	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+60	63	TM4	structure_element	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+88	97	main body	structure_element	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+105	116	transporter	protein_type	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+126	129	CTR	structure_element	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+189	195	Val447	residue_name_number	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+197	203	Asp449	residue_name_number	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+205	211	Pro450	residue_name_number	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+216	222	Arg452	residue_name_number	The AI region packs against the cytoplasmic ends of TM2 and TM4, physically linking the main body of the transporter with the CTR via main chain interactions and side-chain interactions of Val447, Asp449, Pro450 and Arg452 (Fig. 6).	RESULTS
+4	14	AI regions	structure_element	The AI regions have very similar conformations in CaMep2 and ScMep2, despite considerable differences in the rest of the CTR (Fig. 6).	RESULTS
+50	56	CaMep2	protein	The AI regions have very similar conformations in CaMep2 and ScMep2, despite considerable differences in the rest of the CTR (Fig. 6).	RESULTS
+61	67	ScMep2	protein	The AI regions have very similar conformations in CaMep2 and ScMep2, despite considerable differences in the rest of the CTR (Fig. 6).	RESULTS
+121	124	CTR	structure_element	The AI regions have very similar conformations in CaMep2 and ScMep2, despite considerable differences in the rest of the CTR (Fig. 6).	RESULTS
+16	34	Npr1 target serine	site	Strikingly, the Npr1 target serine residue is located at the periphery of the trimer, far away (∼30 Å) from any channel exit (Fig. 6).	RESULTS
+78	84	trimer	oligomeric_state	Strikingly, the Npr1 target serine residue is located at the periphery of the trimer, far away (∼30 Å) from any channel exit (Fig. 6).	RESULTS
+112	124	channel exit	site	Strikingly, the Npr1 target serine residue is located at the periphery of the trimer, far away (∼30 Å) from any channel exit (Fig. 6).	RESULTS
+45	51	trimer	oligomeric_state	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+57	73	electron density	evidence	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+82	88	serine	residue_name	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+113	117	Mep2	protein	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+118	128	structures	evidence	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+152	170	non-phosphorylated	protein_state	Despite its location at the periphery of the trimer, the electron density for the serine is well defined in both Mep2 structures and corresponds to the non-phosphorylated state (Fig. 6).	RESULTS
+132	150	non-phosphorylated	protein_state	This makes sense since the proteins were expressed in rich medium and confirms the recent suggestion by Boeckstaens et al. that the non-phosphorylated form of Mep2 corresponds to the inactive state.	RESULTS
+159	163	Mep2	protein	This makes sense since the proteins were expressed in rich medium and confirms the recent suggestion by Boeckstaens et al. that the non-phosphorylated form of Mep2 corresponds to the inactive state.	RESULTS
+183	191	inactive	protein_state	This makes sense since the proteins were expressed in rich medium and confirms the recent suggestion by Boeckstaens et al. that the non-phosphorylated form of Mep2 corresponds to the inactive state.	RESULTS
+4	10	ScMep2	protein	For ScMep2, Ser457 is the most C-terminal residue for which electron density is visible, indicating that the region beyond Ser457 is disordered.	RESULTS
+12	18	Ser457	residue_name_number	For ScMep2, Ser457 is the most C-terminal residue for which electron density is visible, indicating that the region beyond Ser457 is disordered.	RESULTS
+60	76	electron density	evidence	For ScMep2, Ser457 is the most C-terminal residue for which electron density is visible, indicating that the region beyond Ser457 is disordered.	RESULTS
+123	129	Ser457	residue_name_number	For ScMep2, Ser457 is the most C-terminal residue for which electron density is visible, indicating that the region beyond Ser457 is disordered.	RESULTS
+133	143	disordered	protein_state	For ScMep2, Ser457 is the most C-terminal residue for which electron density is visible, indicating that the region beyond Ser457 is disordered.	RESULTS
+3	9	CaMep2	protein	In CaMep2, the visible part of the sequence extends for two residues beyond Ser453 (Fig. 6).	RESULTS
+76	82	Ser453	residue_name_number	In CaMep2, the visible part of the sequence extends for two residues beyond Ser453 (Fig. 6).	RESULTS
+28	36	disorder	protein_state	The peripheral location and disorder of the CTR beyond the kinase target site should facilitate the phosphorylation by Npr1.	RESULTS
+44	47	CTR	structure_element	The peripheral location and disorder of the CTR beyond the kinase target site should facilitate the phosphorylation by Npr1.	RESULTS
+59	77	kinase target site	site	The peripheral location and disorder of the CTR beyond the kinase target site should facilitate the phosphorylation by Npr1.	RESULTS
+100	115	phosphorylation	ptm	The peripheral location and disorder of the CTR beyond the kinase target site should facilitate the phosphorylation by Npr1.	RESULTS
+119	123	Npr1	protein	The peripheral location and disorder of the CTR beyond the kinase target site should facilitate the phosphorylation by Npr1.	RESULTS
+4	14	disordered	protein_state	The disordered part of the CTR is not conserved in ammonium transporters (Fig. 2), suggesting that it is not important for transport.	RESULTS
+27	30	CTR	structure_element	The disordered part of the CTR is not conserved in ammonium transporters (Fig. 2), suggesting that it is not important for transport.	RESULTS
+34	47	not conserved	protein_state	The disordered part of the CTR is not conserved in ammonium transporters (Fig. 2), suggesting that it is not important for transport.	RESULTS
+51	72	ammonium transporters	protein_type	The disordered part of the CTR is not conserved in ammonium transporters (Fig. 2), suggesting that it is not important for transport.	RESULTS
+17	23	ScMep2	protein	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+24	28	457Δ	mutant	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+29	46	truncation mutant	protein_state	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+83	89	Ser457	residue_name_number	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+118	130	low activity	protein_state	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+211	226	phosphorylation	ptm	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+230	234	Npr1	protein	Interestingly, a ScMep2 457Δ truncation mutant in which a His-tag directly follows Ser457 is highly expressed but has low activity (Fig. 3 and Supplementary Fig. 1b), suggesting that the His-tag interferes with phosphorylation by Npr1.	RESULTS
+9	15	mutant	mutant	The same mutant lacking the His-tag has WT properties (Supplementary Fig. 1b), confirming that the region following the phosphorylation site is dispensable for function.	RESULTS
+16	35	lacking the His-tag	protein_state	The same mutant lacking the His-tag has WT properties (Supplementary Fig. 1b), confirming that the region following the phosphorylation site is dispensable for function.	RESULTS
+40	42	WT	protein_state	The same mutant lacking the His-tag has WT properties (Supplementary Fig. 1b), confirming that the region following the phosphorylation site is dispensable for function.	RESULTS
+120	140	phosphorylation site	site	The same mutant lacking the His-tag has WT properties (Supplementary Fig. 1b), confirming that the region following the phosphorylation site is dispensable for function.	RESULTS
+0	4	Mep2	protein	Mep2 lacking the AI region is conformationally heterogeneous	RESULTS
+5	12	lacking	protein_state	Mep2 lacking the AI region is conformationally heterogeneous	RESULTS
+17	26	AI region	structure_element	Mep2 lacking the AI region is conformationally heterogeneous	RESULTS
+30	60	conformationally heterogeneous	protein_state	Mep2 lacking the AI region is conformationally heterogeneous	RESULTS
+11	17	Ser457	residue_name_number	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+18	21	453	residue_number	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+38	50	channel exit	site	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+89	104	phosphorylation	ptm	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+115	119	Mep2	protein	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+120	127	channel	site	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+143	149	active	protein_state	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+150	161	transporter	protein_type	Given that Ser457/453 is far from any channel exit (Fig. 6), the crucial question is how phosphorylation opens the Mep2 channel to generate an active transporter.	RESULTS
+33	48	phosphorylation	ptm	Boeckstaens et al. proposed that phosphorylation does not affect channel activity directly, but instead relieves inhibition by the AI region.	RESULTS
+131	140	AI region	structure_element	Boeckstaens et al. proposed that phosphorylation does not affect channel activity directly, but instead relieves inhibition by the AI region.	RESULTS
+58	64	ScMep2	protein	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+65	73	449-485Δ	mutant	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+74	89	deletion mutant	protein_state	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+90	97	lacking	protein_state	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+102	111	AI region	structure_element	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+115	128	highly active	protein_state	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+132	134	MA	chemical	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+154	165	triple mepΔ	mutant	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+170	187	triple mepΔ npr1Δ	mutant	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+220	232	Mep2 variant	mutant	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+239	258	constitutively open	protein_state	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+259	266	channel	site	The data behind this hypothesis is the observation that a ScMep2 449-485Δ deletion mutant lacking the AI region is highly active in MA uptake both in the triple mepΔ and triple mepΔ npr1Δ backgrounds, implying that this Mep2 variant has a constitutively open channel.	RESULTS
+56	60	446Δ	mutant	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+61	67	mutant	protein_state	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+125	149	constructed and purified	experimental_method	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+164	170	CaMep2	protein	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+171	175	442Δ	mutant	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+176	193	truncation mutant	protein_state	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+198	208	determined	experimental_method	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+213	230	crystal structure	evidence	We obtained a similar result for ammonium uptake by the 446Δ mutant (Fig. 3), supporting the data from Marini et al. We then constructed and purified the analogous CaMep2 442Δ truncation mutant and determined the crystal structure using data to 3.4 Å resolution.	RESULTS
+4	13	structure	evidence	The structure shows that removal of the AI region markedly increases the dynamics of the cytoplasmic parts of the transporter.	RESULTS
+25	35	removal of	experimental_method	The structure shows that removal of the AI region markedly increases the dynamics of the cytoplasmic parts of the transporter.	RESULTS
+40	49	AI region	structure_element	The structure shows that removal of the AI region markedly increases the dynamics of the cytoplasmic parts of the transporter.	RESULTS
+89	106	cytoplasmic parts	structure_element	The structure shows that removal of the AI region markedly increases the dynamics of the cytoplasmic parts of the transporter.	RESULTS
+114	125	transporter	protein_type	The structure shows that removal of the AI region markedly increases the dynamics of the cytoplasmic parts of the transporter.	RESULTS
+47	56	AI region	structure_element	This is not unexpected given the fact that the AI region bridges the CTR and the main body of Mep2 (Fig. 6).	RESULTS
+69	72	CTR	structure_element	This is not unexpected given the fact that the AI region bridges the CTR and the main body of Mep2 (Fig. 6).	RESULTS
+81	90	main body	structure_element	This is not unexpected given the fact that the AI region bridges the CTR and the main body of Mep2 (Fig. 6).	RESULTS
+94	98	Mep2	protein	This is not unexpected given the fact that the AI region bridges the CTR and the main body of Mep2 (Fig. 6).	RESULTS
+0	7	Density	evidence	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+12	16	ICL3	structure_element	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+25	28	CTR	structure_element	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+44	50	Arg415	residue_name_number	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+69	73	442Δ	mutant	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+74	80	mutant	protein_state	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+90	97	density	evidence	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+112	116	ICLs	structure_element	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+127	131	ICL1	structure_element	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+176	185	structure	evidence	Density for ICL3 and the CTR beyond residue Arg415 is missing in the 442Δ mutant, and the density for the other ICLs including ICL1 is generally poor with visible parts of the structure having high B-factors (Fig. 7).	RESULTS
+28	33	Tyr49	residue_name_number	Interestingly, however, the Tyr49-His342 hydrogen bond that closes the channel in the WT protein is still present (Fig. 7 and Supplementary Fig. 2).	RESULTS
+34	40	His342	residue_name_number	Interestingly, however, the Tyr49-His342 hydrogen bond that closes the channel in the WT protein is still present (Fig. 7 and Supplementary Fig. 2).	RESULTS
+86	88	WT	protein_state	Interestingly, however, the Tyr49-His342 hydrogen bond that closes the channel in the WT protein is still present (Fig. 7 and Supplementary Fig. 2).	RESULTS
+54	60	active	protein_state	Why then does this mutant appear to be constitutively active? We propose two possibilities.	RESULTS
+26	30	open	protein_state	The first one is that the open state is disfavoured by crystallization because of lower stability or due to crystal packing constraints.	RESULTS
+55	70	crystallization	experimental_method	The first one is that the open state is disfavoured by crystallization because of lower stability or due to crystal packing constraints.	RESULTS
+35	56	Tyr–His hydrogen bond	site	The second possibility is that the Tyr–His hydrogen bond has to be disrupted by the incoming substrate to open the channel.	RESULTS
+106	110	open	protein_state	The second possibility is that the Tyr–His hydrogen bond has to be disrupted by the incoming substrate to open the channel.	RESULTS
+41	44	NH3	chemical	The latter model would fit well with the NH3/H+ symport model in which the proton is relayed by the twin-His motif.	RESULTS
+45	47	H+	chemical	The latter model would fit well with the NH3/H+ symport model in which the proton is relayed by the twin-His motif.	RESULTS
+100	114	twin-His motif	structure_element	The latter model would fit well with the NH3/H+ symport model in which the proton is relayed by the twin-His motif.	RESULTS
+22	43	Tyr–His hydrogen bond	site	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+80	87	removal	experimental_method	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+95	101	ScMep2	protein	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+102	106	Y53A	mutant	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+107	113	mutant	protein_state	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+127	148	constitutively active	protein_state	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+149	160	transporter	protein_type	The importance of the Tyr–His hydrogen bond is underscored by the fact that its removal in the ScMep2 Y53A mutant results in a constitutively active transporter (Fig. 3).	RESULTS
+0	15	Phosphorylation	ptm	Phosphorylation causes a conformational change in the CTR	RESULTS
+54	57	CTR	structure_element	Phosphorylation causes a conformational change in the CTR	RESULTS
+7	11	Mep2	protein	Do the Mep2 structures provide any clues regarding the potential effect of phosphorylation?	RESULTS
+12	22	structures	evidence	Do the Mep2 structures provide any clues regarding the potential effect of phosphorylation?	RESULTS
+75	90	phosphorylation	ptm	Do the Mep2 structures provide any clues regarding the potential effect of phosphorylation?	RESULTS
+27	33	Ser457	residue_name_number	The side-chain hydroxyl of Ser457/453 is located in a well-defined electronegative pocket that is solvent accessible (Fig. 6).	RESULTS
+34	37	453	residue_number	The side-chain hydroxyl of Ser457/453 is located in a well-defined electronegative pocket that is solvent accessible (Fig. 6).	RESULTS
+67	89	electronegative pocket	site	The side-chain hydroxyl of Ser457/453 is located in a well-defined electronegative pocket that is solvent accessible (Fig. 6).	RESULTS
+98	116	solvent accessible	protein_state	The side-chain hydroxyl of Ser457/453 is located in a well-defined electronegative pocket that is solvent accessible (Fig. 6).	RESULTS
+25	31	serine	residue_name	The closest atoms to the serine hydroxyl group are the backbone carbonyl atoms of Asp419, Glu420 and Glu421, which are 3–4 Å away.	RESULTS
+82	88	Asp419	residue_name_number	The closest atoms to the serine hydroxyl group are the backbone carbonyl atoms of Asp419, Glu420 and Glu421, which are 3–4 Å away.	RESULTS
+90	96	Glu420	residue_name_number	The closest atoms to the serine hydroxyl group are the backbone carbonyl atoms of Asp419, Glu420 and Glu421, which are 3–4 Å away.	RESULTS
+101	107	Glu421	residue_name_number	The closest atoms to the serine hydroxyl group are the backbone carbonyl atoms of Asp419, Glu420 and Glu421, which are 3–4 Å away.	RESULTS
+26	41	phosphorylation	ptm	We therefore predict that phosphorylation of Ser453 will result in steric clashes as well as electrostatic repulsion, which in turn might cause substantial conformational changes within the CTR.	RESULTS
+45	51	Ser453	residue_name_number	We therefore predict that phosphorylation of Ser453 will result in steric clashes as well as electrostatic repulsion, which in turn might cause substantial conformational changes within the CTR.	RESULTS
+190	193	CTR	structure_element	We therefore predict that phosphorylation of Ser453 will result in steric clashes as well as electrostatic repulsion, which in turn might cause substantial conformational changes within the CTR.	RESULTS
+28	38	determined	experimental_method	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+43	52	structure	evidence	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+60	85	phosphorylation-mimicking	protein_state	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+86	97	R452D/S453D	mutant	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+125	134	DD mutant	mutant	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+179	201	additional mutation of	experimental_method	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+206	214	arginine	residue_name	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+229	249	phosphorylation site	site	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+342	351	phosphate	chemical	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+423	432	AI region	structure_element	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+442	451	main body	structure_element	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+459	470	transporter	protein_type	To test this hypothesis, we determined the structure of the phosphorylation-mimicking R452D/S453D protein (hereafter termed ‘DD mutant'), using data to a resolution of 2.4 Å. The additional mutation of the arginine preceding the phosphorylation site was introduced (i) to increase the negative charge density and make it more comparable to a phosphate at neutral pH, and (ii) to further destabilize the interactions of the AI region with the main body of the transporter (Fig. 6).	RESULTS
+4	12	ammonium	chemical	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+36	49	S. cerevisiae	species	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+65	74	DD mutant	mutant	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+98	100	WT	protein_state	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+101	105	Mep2	protein	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+114	119	S453D	mutant	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+120	126	mutant	protein_state	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+205	216	triple mepΔ	mutant	The ammonium uptake activity of the S. cerevisiae version of the DD mutant is the same as that of WT Mep2 and the S453D mutant, indicating that the mutations do not affect transporter functionality in the triple mepΔ background (Fig. 3).	RESULTS
+18	28	AI segment	structure_element	Unexpectedly, the AI segment containing the mutated residues has only undergone a slight shift compared with the WT protein (Fig. 8 and Supplementary Fig. 3).	RESULTS
+113	115	WT	protein_state	Unexpectedly, the AI segment containing the mutated residues has only undergone a slight shift compared with the WT protein (Fig. 8 and Supplementary Fig. 3).	RESULTS
+17	26	conserved	protein_state	By contrast, the conserved part of the CTR has undergone a large conformational change involving formation of a 12-residue-long α-helix from Leu427 to Asp438.	RESULTS
+39	42	CTR	structure_element	By contrast, the conserved part of the CTR has undergone a large conformational change involving formation of a 12-residue-long α-helix from Leu427 to Asp438.	RESULTS
+112	135	12-residue-long α-helix	structure_element	By contrast, the conserved part of the CTR has undergone a large conformational change involving formation of a 12-residue-long α-helix from Leu427 to Asp438.	RESULTS
+141	157	Leu427 to Asp438	residue_range	By contrast, the conserved part of the CTR has undergone a large conformational change involving formation of a 12-residue-long α-helix from Leu427 to Asp438.	RESULTS
+22	35	Glu420-Leu423	residue_range	In addition, residues Glu420-Leu423 including Glu421 of the ExxGxD motif are now disordered (Fig. 8 and Supplementary Fig. 3).	RESULTS
+46	52	Glu421	residue_name_number	In addition, residues Glu420-Leu423 including Glu421 of the ExxGxD motif are now disordered (Fig. 8 and Supplementary Fig. 3).	RESULTS
+60	72	ExxGxD motif	structure_element	In addition, residues Glu420-Leu423 including Glu421 of the ExxGxD motif are now disordered (Fig. 8 and Supplementary Fig. 3).	RESULTS
+81	91	disordered	protein_state	In addition, residues Glu420-Leu423 including Glu421 of the ExxGxD motif are now disordered (Fig. 8 and Supplementary Fig. 3).	RESULTS
+77	97	ammonium transporter	protein_type	This is the first time a large conformational change has been observed in an ammonium transporter as a result of a mutation, and confirms previous hypotheses that phosphorylation causes structural changes in the CTR.	RESULTS
+115	123	mutation	experimental_method	This is the first time a large conformational change has been observed in an ammonium transporter as a result of a mutation, and confirms previous hypotheses that phosphorylation causes structural changes in the CTR.	RESULTS
+163	178	phosphorylation	ptm	This is the first time a large conformational change has been observed in an ammonium transporter as a result of a mutation, and confirms previous hypotheses that phosphorylation causes structural changes in the CTR.	RESULTS
+212	215	CTR	structure_element	This is the first time a large conformational change has been observed in an ammonium transporter as a result of a mutation, and confirms previous hypotheses that phosphorylation causes structural changes in the CTR.	RESULTS
+47	52	R452D	mutant	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+111	121	determined	experimental_method	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+126	135	structure	evidence	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+144	152	single D	mutant	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+154	159	S453D	mutant	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+160	166	mutant	protein_state	To exclude the possibility that the additional R452D mutation is responsible for the observed changes, we also determined the structure of the ‘single D' S453D mutant.	RESULTS
+57	65	single D	mutant	As shown in Supplementary Fig. 4, the consequence of the single D mutation is very similar to that of the DD substitution, with conformational changes and increased dynamics confined to the conserved part of the CTR (Supplementary Fig. 4).	RESULTS
+66	74	mutation	experimental_method	As shown in Supplementary Fig. 4, the consequence of the single D mutation is very similar to that of the DD substitution, with conformational changes and increased dynamics confined to the conserved part of the CTR (Supplementary Fig. 4).	RESULTS
+106	121	DD substitution	mutant	As shown in Supplementary Fig. 4, the consequence of the single D mutation is very similar to that of the DD substitution, with conformational changes and increased dynamics confined to the conserved part of the CTR (Supplementary Fig. 4).	RESULTS
+190	199	conserved	protein_state	As shown in Supplementary Fig. 4, the consequence of the single D mutation is very similar to that of the DD substitution, with conformational changes and increased dynamics confined to the conserved part of the CTR (Supplementary Fig. 4).	RESULTS
+212	215	CTR	structure_element	As shown in Supplementary Fig. 4, the consequence of the single D mutation is very similar to that of the DD substitution, with conformational changes and increased dynamics confined to the conserved part of the CTR (Supplementary Fig. 4).	RESULTS
+18	36	crystal structures	evidence	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+56	65	modelling	experimental_method	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+70	72	MD	experimental_method	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+84	86	WT	protein_state	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+87	93	CaMep2	protein	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+99	108	DD mutant	mutant	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+113	127	phosphorylated	protein_state	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+137	142	S453J	mutant	To supplement the crystal structures, we also performed modelling and MD studies of WT CaMep2, the DD mutant and phosphorylated protein (S453J).	RESULTS
+7	9	WT	protein_state	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+10	19	structure	evidence	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+41	47	Asp419	residue_name_number	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+49	55	Glu420	residue_name_number	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+60	66	Glu421	residue_name_number	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+107	113	Ser453	residue_name_number	In the WT structure, the acidic residues Asp419, Glu420 and Glu421 are within hydrogen bonding distance of Ser453.	RESULTS
+16	18	MD	experimental_method	After 200 ns of MD simulation, the interactions between these residues and Ser453 remain intact.	RESULTS
+19	29	simulation	experimental_method	After 200 ns of MD simulation, the interactions between these residues and Ser453 remain intact.	RESULTS
+75	81	Ser453	residue_name_number	After 200 ns of MD simulation, the interactions between these residues and Ser453 remain intact.	RESULTS
+36	44	r.m.s.d.	evidence	The protein backbone has an average r.m.s.d. of only ∼3 Å during the 200-ns simulation, indicating that the protein is stable.	RESULTS
+76	86	simulation	experimental_method	The protein backbone has an average r.m.s.d. of only ∼3 Å during the 200-ns simulation, indicating that the protein is stable.	RESULTS
+119	125	stable	protein_state	The protein backbone has an average r.m.s.d. of only ∼3 Å during the 200-ns simulation, indicating that the protein is stable.	RESULTS
+93	99	stable	protein_state	There is flexibility in the side chains of the acidic residues so that they are able to form stable hydrogen bonds with Ser453.	RESULTS
+120	126	Ser453	residue_name_number	There is flexibility in the side chains of the acidic residues so that they are able to form stable hydrogen bonds with Ser453.	RESULTS
+66	72	Ser453	residue_name_number	In particular, persistent hydrogen bonds are observed between the Ser453 hydroxyl group and the acidic group of Glu420, and also between the amine group of Ser453 and the backbone carbonyl of Glu420 (Supplementary Fig. 5).	RESULTS
+112	118	Glu420	residue_name_number	In particular, persistent hydrogen bonds are observed between the Ser453 hydroxyl group and the acidic group of Glu420, and also between the amine group of Ser453 and the backbone carbonyl of Glu420 (Supplementary Fig. 5).	RESULTS
+156	162	Ser453	residue_name_number	In particular, persistent hydrogen bonds are observed between the Ser453 hydroxyl group and the acidic group of Glu420, and also between the amine group of Ser453 and the backbone carbonyl of Glu420 (Supplementary Fig. 5).	RESULTS
+192	198	Glu420	residue_name_number	In particular, persistent hydrogen bonds are observed between the Ser453 hydroxyl group and the acidic group of Glu420, and also between the amine group of Ser453 and the backbone carbonyl of Glu420 (Supplementary Fig. 5).	RESULTS
+4	13	DD mutant	mutant	The DD mutant is also stable during the simulations, but the average backbone r.m.s.d of ∼3.6 Å suggests slightly more conformational flexibility than WT.	RESULTS
+22	28	stable	protein_state	The DD mutant is also stable during the simulations, but the average backbone r.m.s.d of ∼3.6 Å suggests slightly more conformational flexibility than WT.	RESULTS
+40	51	simulations	experimental_method	The DD mutant is also stable during the simulations, but the average backbone r.m.s.d of ∼3.6 Å suggests slightly more conformational flexibility than WT.	RESULTS
+78	85	r.m.s.d	evidence	The DD mutant is also stable during the simulations, but the average backbone r.m.s.d of ∼3.6 Å suggests slightly more conformational flexibility than WT.	RESULTS
+151	153	WT	protein_state	The DD mutant is also stable during the simulations, but the average backbone r.m.s.d of ∼3.6 Å suggests slightly more conformational flexibility than WT.	RESULTS
+7	17	simulation	experimental_method	As the simulation proceeds, the side chains of the acidic residues move away from Asp452 and Asp453, presumably to avoid electrostatic repulsion.	RESULTS
+82	88	Asp452	residue_name_number	As the simulation proceeds, the side chains of the acidic residues move away from Asp452 and Asp453, presumably to avoid electrostatic repulsion.	RESULTS
+93	99	Asp453	residue_name_number	As the simulation proceeds, the side chains of the acidic residues move away from Asp452 and Asp453, presumably to avoid electrostatic repulsion.	RESULTS
+17	25	distance	evidence	For example, the distance between the Asp453 acidic oxygens and the Glu420 acidic oxygens increases from ∼7 to >22 Å after 200 ns simulations, and thus these residues are not interacting.	RESULTS
+38	44	Asp453	residue_name_number	For example, the distance between the Asp453 acidic oxygens and the Glu420 acidic oxygens increases from ∼7 to >22 Å after 200 ns simulations, and thus these residues are not interacting.	RESULTS
+68	74	Glu420	residue_name_number	For example, the distance between the Asp453 acidic oxygens and the Glu420 acidic oxygens increases from ∼7 to >22 Å after 200 ns simulations, and thus these residues are not interacting.	RESULTS
+130	141	simulations	experimental_method	For example, the distance between the Asp453 acidic oxygens and the Glu420 acidic oxygens increases from ∼7 to >22 Å after 200 ns simulations, and thus these residues are not interacting.	RESULTS
+15	34	structurally stable	protein_state	The protein is structurally stable throughout the simulation with little deviation in the other parts of the protein.	RESULTS
+50	60	simulation	experimental_method	The protein is structurally stable throughout the simulation with little deviation in the other parts of the protein.	RESULTS
+13	18	S453J	mutant	Finally, the S453J mutant is also stable throughout the 200-ns simulation and has an average backbone deviation of ∼3.8 Å, which is similar to the DD mutant.	RESULTS
+19	25	mutant	protein_state	Finally, the S453J mutant is also stable throughout the 200-ns simulation and has an average backbone deviation of ∼3.8 Å, which is similar to the DD mutant.	RESULTS
+34	40	stable	protein_state	Finally, the S453J mutant is also stable throughout the 200-ns simulation and has an average backbone deviation of ∼3.8 Å, which is similar to the DD mutant.	RESULTS
+63	73	simulation	experimental_method	Finally, the S453J mutant is also stable throughout the 200-ns simulation and has an average backbone deviation of ∼3.8 Å, which is similar to the DD mutant.	RESULTS
+147	156	DD mutant	mutant	Finally, the S453J mutant is also stable throughout the 200-ns simulation and has an average backbone deviation of ∼3.8 Å, which is similar to the DD mutant.	RESULTS
+46	52	Arg452	residue_name_number	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+57	63	Sep453	residue_name_number	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+91	101	simulation	experimental_method	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+144	150	Asp452	residue_name_number	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+155	161	Asp453	residue_name_number	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+169	178	DD mutant	mutant	The movement of the acidic residues away from Arg452 and Sep453 is more pronounced in this simulation in comparison with the movement away from Asp452 and Asp453 in the DD mutant.	RESULTS
+4	12	distance	evidence	The distance between the phosphate of Sep453 and the acidic oxygen atoms of Glu420 is initially ∼11 Å, but increases to >30 Å after 200 ns.	RESULTS
+25	34	phosphate	chemical	The distance between the phosphate of Sep453 and the acidic oxygen atoms of Glu420 is initially ∼11 Å, but increases to >30 Å after 200 ns.	RESULTS
+38	44	Sep453	residue_name_number	The distance between the phosphate of Sep453 and the acidic oxygen atoms of Glu420 is initially ∼11 Å, but increases to >30 Å after 200 ns.	RESULTS
+76	82	Glu420	residue_name_number	The distance between the phosphate of Sep453 and the acidic oxygen atoms of Glu420 is initially ∼11 Å, but increases to >30 Å after 200 ns.	RESULTS
+4	15	short helix	structure_element	The short helix formed by residues Leu427 to Asp438 unravels during the simulations to a disordered state.	RESULTS
+35	51	Leu427 to Asp438	residue_range	The short helix formed by residues Leu427 to Asp438 unravels during the simulations to a disordered state.	RESULTS
+72	83	simulations	experimental_method	The short helix formed by residues Leu427 to Asp438 unravels during the simulations to a disordered state.	RESULTS
+89	99	disordered	protein_state	The short helix formed by residues Leu427 to Asp438 unravels during the simulations to a disordered state.	RESULTS
+10	12	MD	experimental_method	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+13	24	simulations	experimental_method	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+53	71	crystal structures	evidence	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+77	92	phosphorylation	ptm	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+133	142	conserved	protein_state	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+155	158	CTR	structure_element	Thus, the MD simulations support the notion from the crystal structures that phosphorylation generates conformational changes in the conserved part of the CTR.	RESULTS
+44	66	phosphomimetic mutants	mutant	However, the conformational changes for the phosphomimetic mutants in the crystals are confined to the CTR (Fig. 8), and the channels are still closed (Supplementary Fig. 2).	RESULTS
+74	82	crystals	evidence	However, the conformational changes for the phosphomimetic mutants in the crystals are confined to the CTR (Fig. 8), and the channels are still closed (Supplementary Fig. 2).	RESULTS
+103	106	CTR	structure_element	However, the conformational changes for the phosphomimetic mutants in the crystals are confined to the CTR (Fig. 8), and the channels are still closed (Supplementary Fig. 2).	RESULTS
+125	133	channels	site	However, the conformational changes for the phosphomimetic mutants in the crystals are confined to the CTR (Fig. 8), and the channels are still closed (Supplementary Fig. 2).	RESULTS
+144	150	closed	protein_state	However, the conformational changes for the phosphomimetic mutants in the crystals are confined to the CTR (Fig. 8), and the channels are still closed (Supplementary Fig. 2).	RESULTS
+37	44	mutants	mutant	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+71	84	phosphoserine	residue_name	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+115	120	S453D	mutant	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+125	135	DD mutants	mutant	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+140	152	fully active	protein_state	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+160	170	absence of	protein_state	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+171	175	Npr1	protein	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+194	203	mutations	experimental_method	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+227	242	phosphorylation	ptm	One possible explanation is that the mutants do not accurately mimic a phosphoserine, but the observation that the S453D and DD mutants are fully active in the absence of Npr1 suggests that the mutations do mimic the effect of phosphorylation (Fig. 3).	RESULTS
+18	23	S453D	mutant	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+24	33	structure	evidence	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+72	80	ammonium	chemical	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+104	119	crystallization	experimental_method	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+136	142	closed	protein_state	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+157	161	Mep2	protein	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+162	170	channels	site	The fact that the S453D structure was obtained in the presence of 10 mM ammonium ions suggests that the crystallization process favours closed states of the Mep2 channels.	RESULTS
+16	36	ammonium transporter	protein_type	Knowledge about ammonium transporter structure has been obtained from experimental and theoretical studies on bacterial family members.	DISCUSS
+37	46	structure	evidence	Knowledge about ammonium transporter structure has been obtained from experimental and theoretical studies on bacterial family members.	DISCUSS
+110	119	bacterial	taxonomy_domain	Knowledge about ammonium transporter structure has been obtained from experimental and theoretical studies on bacterial family members.	DISCUSS
+25	56	biochemical and genetic studies	experimental_method	In addition, a number of biochemical and genetic studies are available for bacterial, fungal and plant proteins.	DISCUSS
+75	84	bacterial	taxonomy_domain	In addition, a number of biochemical and genetic studies are available for bacterial, fungal and plant proteins.	DISCUSS
+86	92	fungal	taxonomy_domain	In addition, a number of biochemical and genetic studies are available for bacterial, fungal and plant proteins.	DISCUSS
+97	102	plant	taxonomy_domain	In addition, a number of biochemical and genetic studies are available for bacterial, fungal and plant proteins.	DISCUSS
+159	167	ammonium	chemical	These efforts have advanced our knowledge considerably but have not yet yielded atomic-level answers to several important mechanistic questions, including how ammonium transport is regulated in eukaryotes and the mechanism of ammonium signalling.	DISCUSS
+194	204	eukaryotes	taxonomy_domain	These efforts have advanced our knowledge considerably but have not yet yielded atomic-level answers to several important mechanistic questions, including how ammonium transport is regulated in eukaryotes and the mechanism of ammonium signalling.	DISCUSS
+226	234	ammonium	chemical	These efforts have advanced our knowledge considerably but have not yet yielded atomic-level answers to several important mechanistic questions, including how ammonium transport is regulated in eukaryotes and the mechanism of ammonium signalling.	DISCUSS
+3	23	Arabidopsis thaliana	species	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+24	31	Amt-1;1	protein	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+33	48	phosphorylation	ptm	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+56	59	CTR	structure_element	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+68	72	T460	residue_name_number	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+98	106	ammonium	chemical	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+158	176	non-phosphorylated	protein_state	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+191	196	plant	taxonomy_domain	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+197	208	transporter	protein_type	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+212	216	open	protein_state	In Arabidopsis thaliana Amt-1;1, phosphorylation of the CTR residue T460 under conditions of high ammonium inhibits transport activity, that is, the default (non-phosphorylated) state of the plant transporter is open.	DISCUSS
+15	39	phosphomimetic mutations	mutant	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+60	67	monomer	oligomeric_state	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+90	96	trimer	oligomeric_state	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+158	161	CTR	structure_element	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+196	204	ammonium	chemical	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+228	243	phosphorylation	ptm	Interestingly, phosphomimetic mutations introduced into one monomer inactivate the entire trimer, indicating that (i) heterotrimerization occurs and (ii) the CTR mediates allosteric regulation of ammonium transport activity via phosphorylation.	DISCUSS
+48	53	plant	taxonomy_domain	Owing to the lack of structural information for plant AMTs, the details of channel closure and inter-monomer crosstalk are not yet clear.	DISCUSS
+54	58	AMTs	protein_type	Owing to the lack of structural information for plant AMTs, the details of channel closure and inter-monomer crosstalk are not yet clear.	DISCUSS
+75	82	channel	site	Owing to the lack of structural information for plant AMTs, the details of channel closure and inter-monomer crosstalk are not yet clear.	DISCUSS
+21	26	plant	taxonomy_domain	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+27	39	transporters	protein_type	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+45	53	inactive	protein_state	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+64	77	Mep2 proteins	protein_type	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+103	111	ammonium	chemical	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+116	134	non-phosphorylated	protein_state	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+141	149	channels	site	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+159	165	closed	protein_state	Contrasting with the plant transporters, the inactive states of Mep2 proteins under conditions of high ammonium are non-phosphorylated, with channels that are closed on the cytoplasmic side.	DISCUSS
+23	35	transporters	protein_type	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+44	55	A. thaliana	species	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+56	63	Amt-1;1	protein	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+68	72	Mep2	protein	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+107	122	phosphorylation	ptm	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+124	136	inactivation	protein_state	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+140	146	plants	taxonomy_domain	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+151	161	activation	protein_state	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+165	170	fungi	taxonomy_domain	The reason why similar transporters such as A. thaliana Amt-1;1 and Mep2 are regulated in opposite ways by phosphorylation (inactivation in plants and activation in fungi) is not known.	DISCUSS
+3	8	fungi	taxonomy_domain	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+21	29	ammonium	chemical	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+59	80	ammonium transporters	protein_type	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+111	119	ammonium	chemical	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+145	153	ammonium	chemical	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+168	171	Ato	protein_type	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+172	184	transporters	protein_type	In fungi, preventing ammonium entry via channel closure in ammonium transporters would be one way to alleviate ammonium toxicity, in addition to ammonium excretion via Ato transporters and amino-acid secretion.	DISCUSS
+25	35	structures	evidence	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+39	45	closed	protein_state	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+46	67	ammonium transporters	protein_type	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+72	81	comparing	experimental_method	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+88	98	structures	evidence	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+108	124	permanently open	protein_state	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+125	134	bacterial	taxonomy_domain	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+165	169	Mep2	protein_type	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+170	177	channel	site	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+220	223	CTR	structure_element	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+228	232	ICL1	structure_element	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+237	241	ICL3	structure_element	By determining the first structures of closed ammonium transporters and comparing those structures with the permanently open bacterial proteins, we demonstrate that Mep2 channel closure is likely due to movements of the CTR and ICL1 and ICL3.	DISCUSS
+54	57	CTR	structure_element	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+62	66	ICL1	structure_element	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+67	71	ICL3	structure_element	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+83	87	open	protein_state	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+88	100	transporters	protein_type	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+124	128	ICL3	structure_element	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+160	167	channel	site	More specifically, the close interactions between the CTR and ICL1/ICL3 present in open transporters are disrupted, causing ICL3 to move outwards and block the channel (Figs 4 and 9a).	DISCUSS
+13	17	ICL1	structure_element	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+59	66	channel	site	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+87	91	His2	residue_name_number	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+101	115	twin-His motif	structure_element	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+144	160	highly conserved	protein_state	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+161	169	tyrosine	residue_name	In addition, ICL1 has shifted inwards to contribute to the channel closure by engaging His2 from the twin-His motif via hydrogen bonding with a highly conserved tyrosine hydroxyl group.	DISCUSS
+5	20	phosphorylation	ptm	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+28	32	Npr1	protein	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+33	39	kinase	protein_type	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+55	63	nitrogen	chemical	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+98	107	conserved	protein_state	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+108	120	ExxGxD motif	structure_element	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+170	177	channel	site	Upon phosphorylation by the Npr1 kinase in response to nitrogen limitation, the region around the conserved ExxGxD motif undergoes a conformational change that opens the channel (Fig. 9).	DISCUSS
+17	40	structural similarities	evidence	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+48	56	TM parts	structure_element	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+60	64	Mep2	protein	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+69	76	AfAmt-1	protein	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+100	107	channel	site	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+188	195	channel	site	Importantly, the structural similarities in the TM parts of Mep2 and AfAmt-1 (Fig. 5a) suggest that channel opening/closure does not require substantial changes in the residues lining the channel.	DISCUSS
+16	23	channel	site	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+79	83	open	protein_state	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+133	136	CTR	structure_element	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+171	175	ICL3	structure_element	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+196	203	monomer	oligomeric_state	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+265	272	channel	site	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+300	304	ICL3	structure_element	How exactly the channel opens and whether opening is intra-monomeric are still open questions; it is possible that the change in the CTR may disrupt its interactions with ICL3 of the neighbouring monomer (Fig. 9b), which could result in opening of the neighbouring channel via inward movement of its ICL3.	DISCUSS
+31	39	monomers	oligomeric_state	Owing to the crosstalk between monomers, a single phosphorylation event might lead to opening of the entire trimer, although this has not yet been tested (Fig. 9b).	DISCUSS
+50	65	phosphorylation	ptm	Owing to the crosstalk between monomers, a single phosphorylation event might lead to opening of the entire trimer, although this has not yet been tested (Fig. 9b).	DISCUSS
+108	114	trimer	oligomeric_state	Owing to the crosstalk between monomers, a single phosphorylation event might lead to opening of the entire trimer, although this has not yet been tested (Fig. 9b).	DISCUSS
+15	19	Mep2	protein_type	Whether or not Mep2 channel opening requires, in addition to phosphorylation, disruption of the Tyr–His2 interaction by the ammonium substrate is not yet clear.	DISCUSS
+20	27	channel	site	Whether or not Mep2 channel opening requires, in addition to phosphorylation, disruption of the Tyr–His2 interaction by the ammonium substrate is not yet clear.	DISCUSS
+61	76	phosphorylation	ptm	Whether or not Mep2 channel opening requires, in addition to phosphorylation, disruption of the Tyr–His2 interaction by the ammonium substrate is not yet clear.	DISCUSS
+96	116	Tyr–His2 interaction	site	Whether or not Mep2 channel opening requires, in addition to phosphorylation, disruption of the Tyr–His2 interaction by the ammonium substrate is not yet clear.	DISCUSS
+124	132	ammonium	chemical	Whether or not Mep2 channel opening requires, in addition to phosphorylation, disruption of the Tyr–His2 interaction by the ammonium substrate is not yet clear.	DISCUSS
+40	44	Mep2	protein	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+45	53	channels	site	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+70	80	eukaryotic	taxonomy_domain	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+81	102	ammonium transporters	protein_type	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+108	123	structural data	evidence	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+185	188	CTR	structure_element	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+193	210	cytoplasmic loops	structure_element	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+237	243	closed	protein_state	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+248	252	open	protein_state	Is our model for opening and closing of Mep2 channels valid for other eukaryotic ammonium transporters? Our structural data support previous studies and clarify the central role of the CTR and cytoplasmic loops in the transition between closed and open states.	DISCUSS
+43	56	Mep2 proteins	protein_type	However, even the otherwise highly similar Mep2 proteins of S. cerevisiae and C. albicans have different structures for their CTRs (Fig. 1 and Supplementary Fig. 6).	DISCUSS
+60	73	S. cerevisiae	species	However, even the otherwise highly similar Mep2 proteins of S. cerevisiae and C. albicans have different structures for their CTRs (Fig. 1 and Supplementary Fig. 6).	DISCUSS
+78	89	C. albicans	species	However, even the otherwise highly similar Mep2 proteins of S. cerevisiae and C. albicans have different structures for their CTRs (Fig. 1 and Supplementary Fig. 6).	DISCUSS
+105	115	structures	evidence	However, even the otherwise highly similar Mep2 proteins of S. cerevisiae and C. albicans have different structures for their CTRs (Fig. 1 and Supplementary Fig. 6).	DISCUSS
+126	130	CTRs	structure_element	However, even the otherwise highly similar Mep2 proteins of S. cerevisiae and C. albicans have different structures for their CTRs (Fig. 1 and Supplementary Fig. 6).	DISCUSS
+17	26	AI region	structure_element	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+34	37	CTR	structure_element	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+53	69	Npr1 kinase site	site	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+73	82	conserved	protein_state	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+103	109	fungal	taxonomy_domain	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+110	122	transporters	protein_type	In addition, the AI region of the CTR containing the Npr1 kinase site is conserved in only a subset of fungal transporters, suggesting that the details of the structural changes underpinning regulation vary.	DISCUSS
+40	60	absolutely conserved	protein_state	Nevertheless, given the central role of absolutely conserved residues within the ICL1-ICL3-CTR interaction network (Fig. 4), we propose that the structural basics of fungal ammonium transporter activation are conserved.	DISCUSS
+81	114	ICL1-ICL3-CTR interaction network	site	Nevertheless, given the central role of absolutely conserved residues within the ICL1-ICL3-CTR interaction network (Fig. 4), we propose that the structural basics of fungal ammonium transporter activation are conserved.	DISCUSS
+166	172	fungal	taxonomy_domain	Nevertheless, given the central role of absolutely conserved residues within the ICL1-ICL3-CTR interaction network (Fig. 4), we propose that the structural basics of fungal ammonium transporter activation are conserved.	DISCUSS
+173	181	ammonium	chemical	Nevertheless, given the central role of absolutely conserved residues within the ICL1-ICL3-CTR interaction network (Fig. 4), we propose that the structural basics of fungal ammonium transporter activation are conserved.	DISCUSS
+209	218	conserved	protein_state	Nevertheless, given the central role of absolutely conserved residues within the ICL1-ICL3-CTR interaction network (Fig. 4), we propose that the structural basics of fungal ammonium transporter activation are conserved.	DISCUSS
+14	18	Mep2	protein_type	The fact that Mep2 orthologues of distantly related fungi are fully functional in ammonium transport and signalling in S. cerevisiae supports this notion.	DISCUSS
+52	57	fungi	taxonomy_domain	The fact that Mep2 orthologues of distantly related fungi are fully functional in ammonium transport and signalling in S. cerevisiae supports this notion.	DISCUSS
+82	90	ammonium	chemical	The fact that Mep2 orthologues of distantly related fungi are fully functional in ammonium transport and signalling in S. cerevisiae supports this notion.	DISCUSS
+119	132	S. cerevisiae	species	The fact that Mep2 orthologues of distantly related fungi are fully functional in ammonium transport and signalling in S. cerevisiae supports this notion.	DISCUSS
+33	41	tyrosine	residue_name	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+67	71	His2	residue_name_number	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+75	91	highly conserved	protein_state	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+95	101	fungal	taxonomy_domain	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+102	106	Mep2	protein_type	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+140	162	Tyr–His2 hydrogen bond	site	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+189	194	close	protein_state	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+195	208	Mep2 proteins	protein_type	It should also be noted that the tyrosine residue interacting with His2 is highly conserved in fungal Mep2 orthologues, suggesting that the Tyr–His2 hydrogen bond might be a general way to close Mep2 proteins.	DISCUSS
+16	21	plant	taxonomy_domain	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+22	26	AMTs	protein_type	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+54	69	phosphorylation	ptm	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+73	77	T460	residue_name_number	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+145	149	pore	site	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+158	168	C terminus	structure_element	With regards to plant AMTs, it has been proposed that phosphorylation at T460 generates conformational changes that would close the neighbouring pore via the C terminus.	DISCUSS
+38	52	homology model	experimental_method	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+57	64	Amt-1;1	protein	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+79	83	open	protein_state	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+85	100	archaebacterial	taxonomy_domain	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+101	108	AfAmt-1	protein	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+109	118	structure	evidence	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+145	155	C terminus	structure_element	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+159	166	Amt-1;1	protein	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+208	215	monomer	oligomeric_state	This assumption was based partly on a homology model for Amt-1;1 based on the (open) archaebacterial AfAmt-1 structure, which suggested that the C terminus of Amt-1;1 would extend further to the neighbouring monomer.	DISCUSS
+4	8	Mep2	protein	Our Mep2 structures show that this assumption may not be correct (Fig. 4 and Supplementary Fig. 6).	DISCUSS
+9	19	structures	evidence	Our Mep2 structures show that this assumption may not be correct (Fig. 4 and Supplementary Fig. 6).	DISCUSS
+72	75	CTR	structure_element	In addition, the considerable differences between structurally resolved CTR domains means that the exact environment of T460 in Amt-1;1 is also not known (Supplementary Fig. 6).	DISCUSS
+120	124	T460	residue_name_number	In addition, the considerable differences between structurally resolved CTR domains means that the exact environment of T460 in Amt-1;1 is also not known (Supplementary Fig. 6).	DISCUSS
+128	135	Amt-1;1	protein	In addition, the considerable differences between structurally resolved CTR domains means that the exact environment of T460 in Amt-1;1 is also not known (Supplementary Fig. 6).	DISCUSS
+23	45	structural information	evidence	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+120	127	Amt-1;1	protein	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+195	198	CTR	structure_element	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+203	207	ICL1	structure_element	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+208	212	ICL3	structure_element	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+227	231	Y467	residue_name_number	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+232	236	H239	residue_name_number	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+241	245	D458	residue_name_number	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+246	249	K71	residue_name_number	Based on the available structural information, we consider it more likely that phosphorylation-mediated pore closure in Amt-1;1 is intra-monomeric, via disruption of the interactions between the CTR and ICL1/ICL3 (for example, Y467-H239 and D458-K71).	DISCUSS
+37	43	CaMep2	protein	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+44	49	Tyr49	residue_name_number	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+53	58	plant	taxonomy_domain	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+59	63	AMTs	protein_type	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+83	105	Tyr–His2 hydrogen bond	site	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+121	125	Mep2	protein	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+152	158	closed	protein_state	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+168	173	plant	taxonomy_domain	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+174	186	transporters	protein_type	There is generally no equivalent for CaMep2 Tyr49 in plant AMTs, indicating that a Tyr–His2 hydrogen bond as observed in Mep2 may not contribute to the closed state in plant transporters.	DISCUSS
+16	58	intra-monomeric CTR-ICL1/ICL3 interactions	site	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+98	104	fungal	taxonomy_domain	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+109	114	plant	taxonomy_domain	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+115	136	ammonium transporters	protein_type	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+166	170	open	protein_state	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+171	179	channels	site	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+193	200	lack of	protein_state	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+232	240	inactive	protein_state	We propose that intra-monomeric CTR-ICL1/ICL3 interactions lie at the basis of regulation of both fungal and plant ammonium transporters; close interactions generate open channels, whereas the lack of ‘intra-' interactions leads to inactive states.	DISCUSS
+64	85	phosphorylation sites	site	The need to regulate in opposite ways may be the reason why the phosphorylation sites are in different parts of the CTR, that is, centrally located close to the ExxGxD motif in AMTs and peripherally in Mep2.	DISCUSS
+116	119	CTR	structure_element	The need to regulate in opposite ways may be the reason why the phosphorylation sites are in different parts of the CTR, that is, centrally located close to the ExxGxD motif in AMTs and peripherally in Mep2.	DISCUSS
+161	173	ExxGxD motif	structure_element	The need to regulate in opposite ways may be the reason why the phosphorylation sites are in different parts of the CTR, that is, centrally located close to the ExxGxD motif in AMTs and peripherally in Mep2.	DISCUSS
+177	181	AMTs	protein_type	The need to regulate in opposite ways may be the reason why the phosphorylation sites are in different parts of the CTR, that is, centrally located close to the ExxGxD motif in AMTs and peripherally in Mep2.	DISCUSS
+202	206	Mep2	protein	The need to regulate in opposite ways may be the reason why the phosphorylation sites are in different parts of the CTR, that is, centrally located close to the ExxGxD motif in AMTs and peripherally in Mep2.	DISCUSS
+13	28	phosphorylation	ptm	In this way, phosphorylation can either lead to channel closing (in the case of AMTs) or channel opening in the case of Mep2.	DISCUSS
+48	55	channel	site	In this way, phosphorylation can either lead to channel closing (in the case of AMTs) or channel opening in the case of Mep2.	DISCUSS
+80	84	AMTs	protein_type	In this way, phosphorylation can either lead to channel closing (in the case of AMTs) or channel opening in the case of Mep2.	DISCUSS
+89	96	channel	site	In this way, phosphorylation can either lead to channel closing (in the case of AMTs) or channel opening in the case of Mep2.	DISCUSS
+120	124	Mep2	protein	In this way, phosphorylation can either lead to channel closing (in the case of AMTs) or channel opening in the case of Mep2.	DISCUSS
+64	81	certain mutations	mutant	Our model also provides an explanation for the observation that certain mutations within the CTR completely abolish transport activity.	DISCUSS
+93	96	CTR	structure_element	Our model also provides an explanation for the observation that certain mutations within the CTR completely abolish transport activity.	DISCUSS
+45	52	glycine	residue_name	An example of an inactivating residue is the glycine of the ExxGxD motif of the CTR.	DISCUSS
+60	72	ExxGxD motif	structure_element	An example of an inactivating residue is the glycine of the ExxGxD motif of the CTR.	DISCUSS
+80	83	CTR	structure_element	An example of an inactivating residue is the glycine of the ExxGxD motif of the CTR.	DISCUSS
+0	8	Mutation	experimental_method	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+26	30	G393	residue_name_number	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+34	40	EcAmtB	protein	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+42	46	G456	residue_name_number	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+50	59	AtAmt-1;1	protein	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+73	85	transporters	protein_type	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+100	116	Escherichia coli	species	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+117	121	AmtB	protein	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+126	137	A. thaliana	species	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+138	145	Amt-1;1	protein	Mutation of this residue (G393 in EcAmtB; G456 in AtAmt-1;1) inactivates transporters as diverse as Escherichia coli AmtB and A. thaliana Amt-1;1 (refs).	DISCUSS
+54	57	CTR	structure_element	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+98	101	CTR	structure_element	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+106	110	ICL1	structure_element	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+111	115	ICL3	structure_element	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+139	145	closed	protein_state	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+192	196	Mep2	protein	Such mutations likely cause structural changes in the CTR that prevent close contacts between the CTR and ICL1/ICL3, thereby stabilizing a closed state that may be similar to that observed in Mep2.	DISCUSS
+51	66	phosphorylation	ptm	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+102	112	aquaporins	protein_type	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+117	134	urea transporters	protein_type	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+175	185	eukaryotic	taxonomy_domain	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+186	194	channels	protein_type	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+199	211	transporters	protein_type	Regulation and modulation of membrane transport by phosphorylation is known to occur in, for example, aquaporins and urea transporters, and is likely to be a common theme for eukaryotic channels and transporters.	DISCUSS
+10	25	phosphorylation	ptm	Recently, phosphorylation was also shown to modulate substrate affinity in nitrate transporters.	DISCUSS
+75	95	nitrate transporters	protein_type	Recently, phosphorylation was also shown to modulate substrate affinity in nitrate transporters.	DISCUSS
+16	24	ammonium	chemical	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+36	51	phosphorylation	ptm	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+85	96	A. thaliana	species	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+97	101	AMTs	protein_type	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+110	123	S. cerevisiae	species	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+124	128	Mep2	protein	With respect to ammonium transport, phosphorylation has thus far only been shown for A. thaliana AMTs and for S. cerevisiae Mep2 (refs).	DISCUSS
+13	23	absence of	protein_state	However, the absence of GlnK proteins in eukaryotes suggests that phosphorylation-based regulation of ammonium transport may be widespread.	DISCUSS
+24	37	GlnK proteins	protein_type	However, the absence of GlnK proteins in eukaryotes suggests that phosphorylation-based regulation of ammonium transport may be widespread.	DISCUSS
+41	51	eukaryotes	taxonomy_domain	However, the absence of GlnK proteins in eukaryotes suggests that phosphorylation-based regulation of ammonium transport may be widespread.	DISCUSS
+66	81	phosphorylation	ptm	However, the absence of GlnK proteins in eukaryotes suggests that phosphorylation-based regulation of ammonium transport may be widespread.	DISCUSS
+102	110	ammonium	chemical	However, the absence of GlnK proteins in eukaryotes suggests that phosphorylation-based regulation of ammonium transport may be widespread.	DISCUSS
+16	20	Mep2	protein_type	With respect to Mep2-mediated signalling to induce pseudohyphal growth, two models have been put forward as to how this occurs and why it is specific to Mep2 proteins.	DISCUSS
+153	166	Mep2 proteins	protein_type	With respect to Mep2-mediated signalling to induce pseudohyphal growth, two models have been put forward as to how this occurs and why it is specific to Mep2 proteins.	DISCUSS
+142	163	ammonium transporters	protein_type	In one model, signalling is proposed to depend on the nature of the transported substrate, which might be different in certain subfamilies of ammonium transporters (for example, Mep1/Mep3 versus Mep2).	DISCUSS
+178	182	Mep1	protein	In one model, signalling is proposed to depend on the nature of the transported substrate, which might be different in certain subfamilies of ammonium transporters (for example, Mep1/Mep3 versus Mep2).	DISCUSS
+183	187	Mep3	protein	In one model, signalling is proposed to depend on the nature of the transported substrate, which might be different in certain subfamilies of ammonium transporters (for example, Mep1/Mep3 versus Mep2).	DISCUSS
+195	199	Mep2	protein	In one model, signalling is proposed to depend on the nature of the transported substrate, which might be different in certain subfamilies of ammonium transporters (for example, Mep1/Mep3 versus Mep2).	DISCUSS
+13	16	NH3	chemical	For example, NH3 uniport or symport of NH3/H+ might result in changes in local pH, but NH4+ uniport might not, and this difference might determine signalling.	DISCUSS
+39	42	NH3	chemical	For example, NH3 uniport or symport of NH3/H+ might result in changes in local pH, but NH4+ uniport might not, and this difference might determine signalling.	DISCUSS
+43	45	H+	chemical	For example, NH3 uniport or symport of NH3/H+ might result in changes in local pH, but NH4+ uniport might not, and this difference might determine signalling.	DISCUSS
+87	91	NH4+	chemical	For example, NH3 uniport or symport of NH3/H+ might result in changes in local pH, but NH4+ uniport might not, and this difference might determine signalling.	DISCUSS
+84	88	Mep2	protein	In the other model, signalling is thought to require a distinct conformation of the Mep2 transporter occurring during the transport cycle.	DISCUSS
+89	100	transporter	protein_type	In the other model, signalling is thought to require a distinct conformation of the Mep2 transporter occurring during the transport cycle.	DISCUSS
+118	128	structures	evidence	While the current study does not specifically address the mechanism of signalling underlying pseudohyphal growth, our structures do show that Mep2 proteins can assume different conformations.	DISCUSS
+142	155	Mep2 proteins	protein_type	While the current study does not specifically address the mechanism of signalling underlying pseudohyphal growth, our structures do show that Mep2 proteins can assume different conformations.	DISCUSS
+17	25	ammonium	chemical	It is clear that ammonium transport across biomembranes remains a fascinating and challenging field in large part due to the unique properties of the substrate.	DISCUSS
+4	8	Mep2	protein	Our Mep2 structural work now provides a foundation for future studies to uncover the details of the structural changes that occur during eukaryotic ammonium transport and signaling, and to assess the possibility to utilize small molecules to shut down ammonium sensing and downstream signalling pathways in pathogenic fungi.	DISCUSS
+137	147	eukaryotic	taxonomy_domain	Our Mep2 structural work now provides a foundation for future studies to uncover the details of the structural changes that occur during eukaryotic ammonium transport and signaling, and to assess the possibility to utilize small molecules to shut down ammonium sensing and downstream signalling pathways in pathogenic fungi.	DISCUSS
+148	156	ammonium	chemical	Our Mep2 structural work now provides a foundation for future studies to uncover the details of the structural changes that occur during eukaryotic ammonium transport and signaling, and to assess the possibility to utilize small molecules to shut down ammonium sensing and downstream signalling pathways in pathogenic fungi.	DISCUSS
+252	260	ammonium	chemical	Our Mep2 structural work now provides a foundation for future studies to uncover the details of the structural changes that occur during eukaryotic ammonium transport and signaling, and to assess the possibility to utilize small molecules to shut down ammonium sensing and downstream signalling pathways in pathogenic fungi.	DISCUSS
+318	323	fungi	taxonomy_domain	Our Mep2 structural work now provides a foundation for future studies to uncover the details of the structural changes that occur during eukaryotic ammonium transport and signaling, and to assess the possibility to utilize small molecules to shut down ammonium sensing and downstream signalling pathways in pathogenic fungi.	DISCUSS
+0	24	X-ray crystal structures	evidence	X-ray crystal structures of Mep2 transceptors.	FIG
+28	32	Mep2	protein	X-ray crystal structures of Mep2 transceptors.	FIG
+33	45	transceptors	protein_type	X-ray crystal structures of Mep2 transceptors.	FIG
+4	11	Monomer	oligomeric_state	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+71	76	Amt-1	protein	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+92	105	S. cerevisiae	species	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+106	110	Mep2	protein	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+124	135	C. albicans	species	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+136	140	Mep2	protein	(a) Monomer cartoon models viewed from the side for (left) A. fulgidus Amt-1 (PDB ID 2B2H), S. cerevisiae Mep2 (middle) and C. albicans Mep2 (right).	FIG
+19	23	ICL1	structure_element	The region showing ICL1 (blue), ICL3 (green) and the CTR (red) is boxed for comparison.	FIG
+32	36	ICL3	structure_element	The region showing ICL1 (blue), ICL3 (green) and the CTR (red) is boxed for comparison.	FIG
+53	56	CTR	structure_element	The region showing ICL1 (blue), ICL3 (green) and the CTR (red) is boxed for comparison.	FIG
+4	10	CaMep2	protein	(b) CaMep2 trimer viewed from the intracellular side (right).	FIG
+11	17	trimer	oligomeric_state	(b) CaMep2 trimer viewed from the intracellular side (right).	FIG
+4	11	monomer	oligomeric_state	One monomer is coloured as in a and one monomer is coloured by B-factor (blue, low; red; high).	FIG
+40	47	monomer	oligomeric_state	One monomer is coloured as in a and one monomer is coloured by B-factor (blue, low; red; high).	FIG
+4	7	CTR	structure_element	The CTR is boxed.	FIG
+5	12	Overlay	experimental_method	 (c) Overlay of ScMep2 (grey) and CaMep2 (rainbow), illustrating the differences in the CTRs.	FIG
+16	22	ScMep2	protein	 (c) Overlay of ScMep2 (grey) and CaMep2 (rainbow), illustrating the differences in the CTRs.	FIG
+34	40	CaMep2	protein	 (c) Overlay of ScMep2 (grey) and CaMep2 (rainbow), illustrating the differences in the CTRs.	FIG
+88	92	CTRs	structure_element	 (c) Overlay of ScMep2 (grey) and CaMep2 (rainbow), illustrating the differences in the CTRs.	FIG
+0	21	Sequence conservation	evidence	Sequence conservation in ammonium transporters.	FIG
+25	46	ammonium transporters	protein_type	Sequence conservation in ammonium transporters.	FIG
+0	18	ClustalW alignment	experimental_method	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+22	28	CaMep2	protein	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+30	36	ScMep2	protein	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+38	49	A. fulgidus	species	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+50	55	Amt-1	protein	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+65	69	AmtB	protein	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+74	85	A. thaliana	species	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+86	93	Amt-1;1	protein	ClustalW alignment of CaMep2, ScMep2, A. fulgidus Amt-1, E. coli AmtB and A. thaliana Amt-1;1.	FIG
+46	52	CaMep2	protein	The secondary structure elements observed for CaMep2 are indicated, with the numbers corresponding to the centre of the TM segment.	FIG
+120	130	TM segment	structure_element	The secondary structure elements observed for CaMep2 are indicated, with the numbers corresponding to the centre of the TM segment.	FIG
+4	13	conserved	protein_state	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+14	23	RxK motif	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+27	31	ICL1	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+54	62	ER motif	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+66	70	ICL2	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+84	93	conserved	protein_state	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+94	106	ExxGxD motif	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+114	117	CTR	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+133	142	AI region	structure_element	The conserved RxK motif in ICL1 is boxed in blue, the ER motif in ICL2 in cyan, the conserved ExxGxD motif of the CTR in red and the AI region in yellow.	FIG
+77	85	Phe gate	site	 Coloured residues are functionally important and correspond to those of the Phe gate (blue), the binding site Trp residue (magenta) and the twin-His motif (red).	FIG
+98	110	binding site	site	 Coloured residues are functionally important and correspond to those of the Phe gate (blue), the binding site Trp residue (magenta) and the twin-His motif (red).	FIG
+111	114	Trp	residue_name	 Coloured residues are functionally important and correspond to those of the Phe gate (blue), the binding site Trp residue (magenta) and the twin-His motif (red).	FIG
+4	20	Npr1 kinase site	site	The Npr1 kinase site in the AI region is highlighted pink.	FIG
+28	37	AI region	structure_element	The Npr1 kinase site in the AI region is highlighted pink.	FIG
+39	45	CaMep2	protein	The grey sequences at the C termini of CaMep2 and ScMep2 are not visible in the structures and are likely disordered.	FIG
+50	56	ScMep2	protein	The grey sequences at the C termini of CaMep2 and ScMep2 are not visible in the structures and are likely disordered.	FIG
+80	90	structures	evidence	The grey sequences at the C termini of CaMep2 and ScMep2 are not visible in the structures and are likely disordered.	FIG
+99	116	likely disordered	protein_state	The grey sequences at the C termini of CaMep2 and ScMep2 are not visible in the structures and are likely disordered.	FIG
+0	6	Growth	experimental_method	Growth of ScMep2 variants on low ammonium medium.	FIG
+10	25	ScMep2 variants	mutant	Growth of ScMep2 variants on low ammonium medium.	FIG
+8	19	triple mepΔ	mutant	(a) The triple mepΔ strain (black) and triple mepΔ npr1Δ strain (grey) containing plasmids expressing WT and variant ScMep2 were grown on minimal medium containing 1 mM ammonium sulphate.	FIG
+102	104	WT	protein_state	(a) The triple mepΔ strain (black) and triple mepΔ npr1Δ strain (grey) containing plasmids expressing WT and variant ScMep2 were grown on minimal medium containing 1 mM ammonium sulphate.	FIG
+109	123	variant ScMep2	mutant	(a) The triple mepΔ strain (black) and triple mepΔ npr1Δ strain (grey) containing plasmids expressing WT and variant ScMep2 were grown on minimal medium containing 1 mM ammonium sulphate.	FIG
+129	152	grown on minimal medium	experimental_method	(a) The triple mepΔ strain (black) and triple mepΔ npr1Δ strain (grey) containing plasmids expressing WT and variant ScMep2 were grown on minimal medium containing 1 mM ammonium sulphate.	FIG
+169	186	ammonium sulphate	chemical	(a) The triple mepΔ strain (black) and triple mepΔ npr1Δ strain (grey) containing plasmids expressing WT and variant ScMep2 were grown on minimal medium containing 1 mM ammonium sulphate.	FIG
+15	27	cell density	evidence	The quantified cell density reflects logarithmic growth after 24 h. Error bars are the s.d. for three replicates of each strain (b) The strains used in a were also serially diluted and spotted onto minimal agar plates containing glutamate (0.1%) or ammonium sulphate (1 mM), and grown for 3 days at 30 °C.	FIG
+229	238	glutamate	chemical	The quantified cell density reflects logarithmic growth after 24 h. Error bars are the s.d. for three replicates of each strain (b) The strains used in a were also serially diluted and spotted onto minimal agar plates containing glutamate (0.1%) or ammonium sulphate (1 mM), and grown for 3 days at 30 °C.	FIG
+249	266	ammonium sulphate	chemical	The quantified cell density reflects logarithmic growth after 24 h. Error bars are the s.d. for three replicates of each strain (b) The strains used in a were also serially diluted and spotted onto minimal agar plates containing glutamate (0.1%) or ammonium sulphate (1 mM), and grown for 3 days at 30 °C.	FIG
+31	35	Mep2	protein	Structural differences between Mep2 and bacterial ammonium transporters.	FIG
+40	49	bacterial	taxonomy_domain	Structural differences between Mep2 and bacterial ammonium transporters.	FIG
+4	8	ICL1	structure_element	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+12	19	AfAmt-1	protein	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+37	43	CaMep2	protein	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+102	108	fungal	taxonomy_domain	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+164	168	ICL1	structure_element	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+170	174	ICL3	structure_element	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+191	194	CTR	structure_element	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+204	211	AfAmt-1	protein	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+232	238	CaMep2	protein	(a) ICL1 in AfAmt-1 (light blue) and CaMep2 (dark blue), showing unwinding and inward movement in the fungal protein. (b) Stereo diagram viewed from the cytosol of ICL1, ICL3 (green) and the CTR (red) in AfAmt-1 (light colours) and CaMep2 (dark colours).	FIG
+35	44	RxK motif	structure_element	The side chains of residues in the RxK motif as well as those of Tyr49 and His342 are labelled.	FIG
+65	70	Tyr49	residue_name_number	The side chains of residues in the RxK motif as well as those of Tyr49 and His342 are labelled.	FIG
+75	81	His342	residue_name_number	The side chains of residues in the RxK motif as well as those of Tyr49 and His342 are labelled.	FIG
+22	28	CaMep2	protein	 The numbering is for CaMep2.	FIG
+4	13	Conserved	protein_state	(c) Conserved residues in ICL1-3 and the CTR.	FIG
+26	32	ICL1-3	structure_element	(c) Conserved residues in ICL1-3 and the CTR.	FIG
+41	44	CTR	structure_element	(c) Conserved residues in ICL1-3 and the CTR.	FIG
+27	33	CaMep2	protein	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+45	52	AfAmt-1	protein	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+112	121	conserved	protein_state	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+134	138	ICL1	structure_element	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+158	162	ICL2	structure_element	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+164	172	ER motif	structure_element	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+181	185	ICL3	structure_element	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+202	205	CTR	structure_element	Views from the cytosol for CaMep2 (left) and AfAmt-1, highlighting the large differences in conformation of the conserved residues in ICL1 (RxK motif; blue), ICL2 (ER motif; cyan), ICL3 (green) and the CTR (red).	FIG
+48	58	structures	evidence	The labelled residues are analogous within both structures.	FIG
+30	36	trimer	oligomeric_state	In b and c, the centre of the trimer is at top.	FIG
+20	24	Mep2	protein	Channel closures in Mep2.	FIG
+11	24	superposition	experimental_method	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+28	35	AfAmt-1	protein	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+40	46	CaMep2	protein	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+75	83	Phe gate	site	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+85	89	His2	residue_name_number	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+97	111	twin-His motif	structure_element	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+120	128	tyrosine	residue_name	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+137	140	Y49	residue_name_number	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+144	147	TM1	structure_element	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+180	184	His2	residue_name_number	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+188	194	CaMep2	protein	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+271	284	channel block	structure_element	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+314	320	CaMep2	protein	(a) Stereo superposition of AfAmt-1 and CaMep2 showing the residues of the Phe gate, His2 of the twin-His motif and the tyrosine residue Y49 in TM1 that forms a hydrogen bond with His2 in CaMep2. (b) Surface views from the side in rainbow colouring, showing the two-tier channel block (indicated by the arrows) in CaMep2.	FIG
+4	8	Npr1	protein	The Npr1 kinase target Ser453 is dephosphorylated and located in an electronegative pocket.	FIG
+9	15	kinase	protein_type	The Npr1 kinase target Ser453 is dephosphorylated and located in an electronegative pocket.	FIG
+23	29	Ser453	residue_name_number	The Npr1 kinase target Ser453 is dephosphorylated and located in an electronegative pocket.	FIG
+33	49	dephosphorylated	protein_state	The Npr1 kinase target Ser453 is dephosphorylated and located in an electronegative pocket.	FIG
+68	90	electronegative pocket	site	The Npr1 kinase target Ser453 is dephosphorylated and located in an electronegative pocket.	FIG
+19	25	CaMep2	protein	(a) Stereoviews of CaMep2 showing 2Fo–Fc electron density (contoured at 1.0 σ) for CTR residues Asp419-Met422 and for Tyr446-Thr455 of the AI region.	FIG
+83	86	CTR	structure_element	(a) Stereoviews of CaMep2 showing 2Fo–Fc electron density (contoured at 1.0 σ) for CTR residues Asp419-Met422 and for Tyr446-Thr455 of the AI region.	FIG
+96	109	Asp419-Met422	residue_range	(a) Stereoviews of CaMep2 showing 2Fo–Fc electron density (contoured at 1.0 σ) for CTR residues Asp419-Met422 and for Tyr446-Thr455 of the AI region.	FIG
+118	131	Tyr446-Thr455	residue_range	(a) Stereoviews of CaMep2 showing 2Fo–Fc electron density (contoured at 1.0 σ) for CTR residues Asp419-Met422 and for Tyr446-Thr455 of the AI region.	FIG
+139	148	AI region	structure_element	(a) Stereoviews of CaMep2 showing 2Fo–Fc electron density (contoured at 1.0 σ) for CTR residues Asp419-Met422 and for Tyr446-Thr455 of the AI region.	FIG
+4	19	phosphorylation	ptm	The phosphorylation target residue Ser453 is labelled in bold.	FIG
+35	41	Ser453	residue_name_number	The phosphorylation target residue Ser453 is labelled in bold.	FIG
+4	11	Overlay	experimental_method	(b) Overlay of the CTRs of ScMep2 (grey) and CaMep2 (green), showing the similar electronegative environment surrounding the phosphorylation site (P).	FIG
+19	23	CTRs	structure_element	(b) Overlay of the CTRs of ScMep2 (grey) and CaMep2 (green), showing the similar electronegative environment surrounding the phosphorylation site (P).	FIG
+27	33	ScMep2	protein	(b) Overlay of the CTRs of ScMep2 (grey) and CaMep2 (green), showing the similar electronegative environment surrounding the phosphorylation site (P).	FIG
+45	51	CaMep2	protein	(b) Overlay of the CTRs of ScMep2 (grey) and CaMep2 (green), showing the similar electronegative environment surrounding the phosphorylation site (P).	FIG
+125	145	phosphorylation site	site	(b) Overlay of the CTRs of ScMep2 (grey) and CaMep2 (green), showing the similar electronegative environment surrounding the phosphorylation site (P).	FIG
+4	14	AI regions	structure_element	The AI regions are coloured magenta.	FIG
+28	32	Mep2	protein	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+33	39	trimer	oligomeric_state	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+78	84	Ser453	residue_name_number	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+93	106	channel exits	site	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+117	122	Ile52	residue_name_number	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+134	146	channel exit	site	(c) Cytoplasmic view of the Mep2 trimer indicating the large distance between Ser453 and the channel exits (circles; Ile52 lining the channel exit is shown).	FIG
+10	17	removal	experimental_method	Effect of removal of the AI region on Mep2 structure.	FIG
+25	34	AI region	structure_element	Effect of removal of the AI region on Mep2 structure.	FIG
+38	42	Mep2	protein	Effect of removal of the AI region on Mep2 structure.	FIG
+43	52	structure	evidence	Effect of removal of the AI region on Mep2 structure.	FIG
+19	21	WT	protein_state	(a) Side views for WT CaMep2 (left) and the truncation mutant 442Δ (right).	FIG
+22	28	CaMep2	protein	(a) Side views for WT CaMep2 (left) and the truncation mutant 442Δ (right).	FIG
+44	61	truncation mutant	protein_state	(a) Side views for WT CaMep2 (left) and the truncation mutant 442Δ (right).	FIG
+62	66	442Δ	mutant	(a) Side views for WT CaMep2 (left) and the truncation mutant 442Δ (right).	FIG
+78	86	disorder	protein_state	The latter is shown as a putty model according to B-factors to illustrate the disorder in the protein on the cytoplasmic side.	FIG
+42	56	superpositions	experimental_method	 Missing regions are labelled. (b) Stereo superpositions of WT CaMep2 and the truncation mutant.	FIG
+60	62	WT	protein_state	 Missing regions are labelled. (b) Stereo superpositions of WT CaMep2 and the truncation mutant.	FIG
+63	69	CaMep2	protein	 Missing regions are labelled. (b) Stereo superpositions of WT CaMep2 and the truncation mutant.	FIG
+78	95	truncation mutant	protein_state	 Missing regions are labelled. (b) Stereo superpositions of WT CaMep2 and the truncation mutant.	FIG
+58	63	Tyr49	residue_name_number	2Fo–Fc electron density (contoured at 1.0 σ) for residues Tyr49 and His342 is shown for the truncation mutant.	FIG
+68	74	His342	residue_name_number	2Fo–Fc electron density (contoured at 1.0 σ) for residues Tyr49 and His342 is shown for the truncation mutant.	FIG
+92	109	truncation mutant	protein_state	2Fo–Fc electron density (contoured at 1.0 σ) for residues Tyr49 and His342 is shown for the truncation mutant.	FIG
+0	15	Phosphorylation	ptm	Phosphorylation causes conformational changes in the CTR.	FIG
+53	56	CTR	structure_element	Phosphorylation causes conformational changes in the CTR.	FIG
+28	37	DD mutant	mutant	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+38	44	trimer	oligomeric_state	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+51	53	WT	protein_state	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+54	60	CaMep2	protein	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+61	71	superposed	experimental_method	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+95	103	monomers	oligomeric_state	(a) Cytoplasmic view of the DD mutant trimer, with WT CaMep2 superposed in grey for one of the monomers.	FIG
+24	44	phosphorylation site	site	The arrow indicates the phosphorylation site.	FIG
+4	13	AI region	structure_element	The AI region is coloured magenta.	FIG
+4	11	Monomer	oligomeric_state	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+22	35	superposition	experimental_method	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+39	41	WT	protein_state	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+42	48	CaMep2	protein	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+57	66	DD mutant	mutant	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+126	138	ExxGxD motif	structure_element	(b) Monomer side-view superposition of WT CaMep2 and the DD mutant, showing the conformational change and disorder around the ExxGxD motif.	FIG
+25	28	452	residue_number	Side chains for residues 452 and 453 are shown as stick models.	FIG
+33	36	453	residue_number	Side chains for residues 452 and 453 are shown as stick models.	FIG
+56	60	Mep2	protein	Schematic model for phosphorylation-based regulation of Mep2 ammonium transporters.	FIG
+11	17	closed	protein_state	(a) In the closed, non-phosphorylated state (i), the CTR (magenta) and ICL3 (green) are far apart with the latter blocking the intracellular channel exit (indicated with a hatched circle).	FIG
+19	37	non-phosphorylated	protein_state	(a) In the closed, non-phosphorylated state (i), the CTR (magenta) and ICL3 (green) are far apart with the latter blocking the intracellular channel exit (indicated with a hatched circle).	FIG
+53	56	CTR	structure_element	(a) In the closed, non-phosphorylated state (i), the CTR (magenta) and ICL3 (green) are far apart with the latter blocking the intracellular channel exit (indicated with a hatched circle).	FIG
+71	75	ICL3	structure_element	(a) In the closed, non-phosphorylated state (i), the CTR (magenta) and ICL3 (green) are far apart with the latter blocking the intracellular channel exit (indicated with a hatched circle).	FIG
+141	153	channel exit	site	(a) In the closed, non-phosphorylated state (i), the CTR (magenta) and ICL3 (green) are far apart with the latter blocking the intracellular channel exit (indicated with a hatched circle).	FIG
+5	20	phosphorylation	ptm	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+25	33	mimicked	protein_state	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+41	47	CaMep2	protein	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+48	53	S453D	mutant	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+58	68	DD mutants	mutant	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+97	109	ExxGxD motif	structure_element	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+164	167	CTR	structure_element	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+203	207	ICL3	structure_element	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+221	228	channel	site	Upon phosphorylation and mimicked by the CaMep2 S453D and DD mutants (ii), the region around the ExxGxD motif undergoes a conformational change that results in the CTR interacting with the inward-moving ICL3, opening the channel (full circle) (iii).	FIG
+4	8	open	protein_state	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+9	16	channel	site	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+17	21	Mep2	protein	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+22	31	structure	evidence	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+50	65	archaebacterial	taxonomy_domain	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+66	71	Amt-1	protein	The open-channel Mep2 structure is represented by archaebacterial Amt-1 and shown in lighter colours consistent with Fig. 4.	FIG
+71	76	plant	taxonomy_domain	As discussed in the text, similar structural arrangements may occur in plant AMTs.	FIG
+77	81	AMTs	protein_type	As discussed in the text, similar structural arrangements may occur in plant AMTs.	FIG
+26	30	open	protein_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+31	38	channel	site	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+58	76	non-phosphorylated	protein_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+84	99	phosphorylation	ptm	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+144	151	channel	site	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+216	231	phosphorylation	ptm	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+237	241	Mep2	protein	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+242	249	monomer	oligomeric_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+271	275	open	protein_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+276	284	channels	site	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+299	305	trimer	oligomeric_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+353	356	CTR	structure_element	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+361	365	ICL3	structure_element	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG
+384	391	monomer	oligomeric_state	In this case however, the open channel corresponds to the non-phosphorylated state; phosphorylation breaks the CTR–ICL3 interactions leading to channel closure. (b) Model based on AMT transporter analogy showing how phosphorylation of a Mep2 monomer might allosterically open channels in the entire trimer via disruption of the interactions between the CTR and ICL3 of a neighbouring monomer (arrow).	FIG