Protein: BXB_CLOBO
Sequence: MPVTINNFNYNDPIDNNNIIMMEPPFARGTGRYYKAFKITDRIWIIPERYTFGYKPEDFNKSSGIFNRDVCEYYDPDYLNTNDKKNIFLQTMIKLFNRIKSKPLGEKLLEMIINGIPYLGDRRVPLEEFNTNIASVTVNKLISNPGEVERKKGIFANLIIFGPGPVLNENETIDIGIQNHFASREGFGGIMQMKFCPEYVSVFNNVQENKGASIFNRRGYFSDPALILMHELIHVLHGLYGIKVDDLPIVPNEKKFFMQSTDAIQAEELYTFGGQDPSIITPSTDKSIYDKVLQNFRGIVDRLNKVLVCISDPNININIYKNKFKDKYKFVEDSEGKYSIDVESFDKLYKSLMFGFTETNIAENYKIKTRASYFSDSLPPVKIKNLLDNEIYTIEEGFNISDKDMEKEYRGQNKAINKQAYEEISKEHLAVYKIQMCKSVKAPGICIDVDNEDLFFIADKNSFSDDLSKNERIEYNTQSNYIENDFPINELILDTDLISKIELPSENTESLTDFNVDVPVYEKQPAIKKIFTDENTIFQYLYSQTFPLDIRDISLTSSFDDALLFSNKVYSFFSMDYIKTANKVVEAGLFAGWVKQIVNDFVIEANKSNTMDKIADISLIVPYIGLALNVGNETAKGNFENAFEIAGASILLEFIPELLIPVVGAFLLESYIDNKNKIIKTIDNALTKRNEKWSDMYGLIVAQWLSTVNTQFYTIKEGMYKALNYQAQALEEIIKYRYNIYSEKEKSNINIDFNDINSKLNEGINQAIDNINNFINGCSVSYLMKKMIPLAVEKLLDFDNTLKKNLLNYIDENKLYLIGSAEYEKSKVNKYLKTIMPFDLSIYTNDTILIEMFNKYNSEILNNIILNLRYKDNNLIDLSGYGAKVEVYDGVELNDKNQFKLTSSANSKIRVTQNQNIIFNSVFLDFSVSFWIRIPKYKNDGIQNYIHNEYTIINCMKNNSGWKISIRGNRIIWTLIDINGKTKSVFFEYNIREDISEYINRWFFVTITNNLNNAKIYINGKLESNTDIKDIREVIANGEIIFKLDGDIDRTQFIWMKYFSIFNTELSQSNIEERYKIQSYSEYLKDFWGNPLMYNKEYYMFNAGNKNSYIKLKKDSPVGEILTRSKYNQNSKYINYRDLYIGEKFIIRRKSNSQSINDDIVRKEDYIYLDFFNLNQEWRVYTYKYFKKEEEKLFLAPISDSDEFYNTIQIKEYDEQPTYSCQLLFKKDEESTDEIGLIGIHRFYESGIVFEEYKDYFCISKWYLKEVKRKPYNLKLGCNWQFIPKDEGWTE
What is the function of this protein?
Responsible for host epithelial cell transcytosis, host nerve cell targeting and translocation of light chain (LC) into host cytosol.  Composed of 3 subdomains; the translocation domain (TD), and N-terminus and C-terminus of the receptor-binding domain (RBD).  The N-terminus of the TD wraps an extended belt around the perimeter of the LC; it does not seem to protect the active site, but might prevent premature LC dissociation from the translocation channel and protect toxin prior to translocation (PubMed:10932256, PubMed:17167418).  Has 2 coreceptors; complex gangliosides found primarily on neural tissue and host synaptotagmin-1 and -2 (SYT1 and SYT2) which bind simultaneously to adjacent but separate sites at the tip of the HC (PubMed:8144634, PubMed:17185412, PubMed:17167421, PubMed:17167418, PubMed:23807078).  HC alone partially prevents uptake of whole toxin by neural cells, and delays paralysis onset by 160% (PubMed:10413679).  Binding probably positions the TD for integration into the synaptic vesicle membrane (PubMed:17167418, PubMed:23807078).  The HC forms channels at low pH that mediate transport of the light chain (LC) from the endocytic vesicle to the cytosol (PubMed:3856850).  Binds gangliosides GD1b and GT1b (PubMed:10413679, PubMed:14731268).  Gangliosides are not only a coreceptor, but also required for uptake into nerve cells (PubMed:21925111, PubMed:17167418).  HC alone binds to host receptor proteins SYT1 and SYT2 (PubMed:14504267, PubMed:15123599, PubMed:17185412, PubMed:19650874).  Interaction with SYT1 protein does not require SYT1 glycosylation (PubMed:19476346).  The HC C-terminus (approximately residues 1079-1291) interacts with host SYT2 (PubMed:15123599, PubMed:17167421, PubMed:17167418, PubMed:23807078).  Has higher affinity for SYT2 than SYT1 (PubMed:17185412, PubMed:17167421).  Significantly decreases uptake and toxicity of whole BoNT/B and BoNT/G (PubMed:19650874).
What are the official names of this protein?
Botulinum neurotoxin type B, BoNT/B, Bontoxilysin-B.
What is the protein family that this protein belongs to?
Belongs to the peptidase M27 family.
What are the subcellular locations of this protein?
[Botulinum neurotoxin type B]: Secreted. Host synapse, host presynaptic cell membrane. Note=Colocalizes with its SYT1 receptor, probably in synaptic vesicles (PubMed:14504267). At pH 4.4 in the presence of ganglioside GT1b becomes a membrane-associated hydrophobic protein (PubMed:21925111). SUBCELLULAR LOCATION: [Botulinum neurotoxin B light chain]: Secreted. Host cytoplasm, host cytosol. SUBCELLULAR LOCATION: [Botulinum neurotoxin B heavy chain]: Secreted. Host synapse, host presynaptic cell membrane. Host cytoplasmic vesicle, host secretory vesicle, host synaptic vesicle membrane; Multi-pass membrane protein.