Protein: Bifunctional lycopene cyclase/phytoene synthase (Protein albino-2) [Includes: Lycopene beta-cyclase (EC 5.5.1.19) (Carotene cyclase) (Lycopene cyclase); Phytoene synthase (EC 2.5.1.32)] (P37295)
Organism: Neurospora crassa (strain ATCC 24698 / 74-OR23-1A / CBS 708.71 / DSM 1257 / FGSC 987)
Function: Bifunctional enzyme that catalyzes the reactions from geranylgeranyl diphosphate to phytoene (phytoene synthase) and from lycopene to beta-carotene via the intermediate gamma-carotene and from 3,4-didehydrolycopene to torulene (lycopene cyclase). Torulene is further processed to the acidic carotenoid neurosporaxanthin. The cyclase preferentially catalyzes single cyclizations at only one end of the substrate to produce monocyclic carotenoids. Neurosporaxanthin is synthesized from geranyl-geranyl pyrophosphate (GGPP) through several enzymatic activities. Phytoene synthase activity performed by the bifunctional enzyme al-2 first produces phytoene from geranyl-geranyl pyrophosphate (GGPP). The phytoene dehydrogenase al-1 then introduces 5 desaturations to lead to 3,4-didehydrolycopene via the intermediates phytofluene, zeta-carotene, neurosporene and lycopene. Al-2 cyclase activity then converts 3,4-didehydrolycopene into torulene. Al-2 can also convet lycopene into gamma-carotene which in turn is converted to beta-carotene by an additional al-2 cyclization reaction. Torulene is the substrate of the dioxidase cao-2 that breaks the molecule, removing five carbon atoms to yield beta-apo-4'-carotenal, whereas the aldehyde dehydrogenase ylo-1 mediates the last step by converting beta-apo-4'-carotenal into neurosporaxanthin (Probable).
Subcellular location: Membrane {ECO:0000305}; Multi-pass membrane protein {ECO:0000305}.
Sequence: MYDYAFVHLKFTVPAAVLLTAIAYPILNRIHLIQTGFLVVVAFTAALPWDAYLIKHKVWSYPPEAIVGPRLLGIPFEELFFFVIQTYITALVYILFNKPVLHALHLNNQQNPPAWMRVVKVTGQVVLVALSVWGWNAAQVHQETSYLGLILVWACPFLLAIWTLAGRFILSLPWYATVLPMFLPTFYLWAVDEFALHRGTWSIGSGTKLDFCLFGKLDIEEATFFLVTNMLIVGGMAAFDQYLAVIYAFPTLFPKVNRYPTTHMLLQSRLINTSRYDLERIEGLREAVERLRLKSRSFYLANSLFSGRLRIDLILLYSFCRLADDLVDDAKSRREVLSWTAKLNHFLDLHYKDADATEDPKKKAERIDAYIKTAFPPCAYQALHLLPTHILPPKPLYDLIKGFEMDSQFTFHGTSDSTDLQYPIADDKDLENYAIYVAGTVGELCIALIIYHCLPDMSDTQKRELETAACRMGIALQYVNIARDIVVDARIGRVYLPTTWLKKEGLTHKMVLENPEGPEVIERMRRRLLENAFELYGGARPEMQRIPSEARGPMIGAVENYMAIGRVLRERKEGTVFVRMEGRATVPKRRRLSTLLRALYEQ
InterPro domains: - IPR017825: Lycopene cyclase domain (domain) [2-235]
- IPR002060: Squalene/phytoene synthase (family) [292-590]
- IPR044843: Trans-isoprenyl diphosphate synthases, bacterial-type (family) [282-600]
- IPR033904: Trans-isoprenyl diphosphate synthases, head-to-head (domain) [285-591]
- IPR008949: Isoprenoid synthase domain superfamily (homologous_superfamily) [279-600]
- IPR019845: Squalene/phytoene synthase, conserved site (conserved_site) [433-497]
Interaction partners: - Phytoene desaturase
- Geranylgeranyl pyrophosphate synthase
- Carotenoid dioxygenase
- Farnesyl pyrophosphate synthase
- Probable hexaprenyl pyrophosphate synthase, mitochondrial
- 3-keto-steroid reductase
- Squalene monooxygenase
- Protein farnesyltransferase/geranylgeranyltransferase type-1 subunit alpha
- Hydroxymethylglutaryl-CoA synthase
- ditrans,polycis-polyprenyl diphosphate synthase [
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0003824 (catalytic activity), GO:0016853 (isomerase activity), GO:0016740 (transferase activity), GO:0016787 (hydrolase activity), GO:0009975 (cyclase activity), GO:0016817 (hydrolase activity, acting on acid anhydrides), GO:0016765 (transferase activity, transferring alkyl or aryl (other than methyl) groups), GO:0016860 (intramolecular oxidoreductase activity), GO:0004659 (prenyltransferase activity), GO:0016818 (hydrolase activity, acting on acid anhydrides, in phosphorus-containing anhydrides), GO:0016462 (pyrophosphatase activity), GO:0004337 (geranyltranstransferase activity)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0009058 (biosynthetic process), GO:0044237 (cellular metabolic process), GO:0071704 (organic substance metabolic process), GO:0044238 (primary metabolic process), GO:0044255 (cellular lipid metabolic process), GO:0044249 (cellular biosynthetic process), GO:0120252 (hydrocarbon metabolic process), GO:1901576 (organic substance biosynthetic process), GO:0006629 (lipid metabolic process), GO:0006720 (isoprenoid metabolic process), GO:0042214 (terpene metabolic process), GO:0120251 (hydrocarbon biosynthetic process), GO:0008299 (isoprenoid biosynthetic process), GO:0008610 (lipid biosynthetic process), GO:0016119 (carotene metabolic process), GO:0046246 (terpene biosynthetic process)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0016020 (membrane), GO:0005737 (cytoplasm), GO:0012505 (endomembrane system), GO:0031984 (organelle subcompartment), GO:0042175 (nuclear outer membrane-endoplasmic reticulum membrane network), GO:0031090 (organelle membrane), GO:0005783 (endoplasmic reticulum), GO:0043229 (intracellular organelle), GO:0043227 (membrane-bounded organelle), GO:0098827 (endoplasmic reticulum subcompartment), GO:0043231 (intracellular membrane-bounded organelle), GO:0005789 (endoplasmic reticulum membrane)