This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Cofactors, Prosthetic Groups, Electron Carriers Biosynthesis|
Some taxa known to possess this pathway include : Anabaena variabilis , Gloeobacter violaceus , Nostoc punctiforme , Nostoc sp. PCC 7120 , Prochlorococcus marinus pastoris CCMP1986 , Synechococcus elongatus PCC 7942 , Synechocystis sp. PCC 6803
Expected Taxonomic Range: Cyanobacteria
Phytobilins are linear tetrapyrrole molecules that are synthesized by plants, algae and cyanobacteria. Major classes of phytobilins are:
Phycobiliproteins are light-harvesting accessory pigments of cyanobacteria, red algae and cryptophytes, and phytochromes are photoreversible light signal-transducing pigments of plants, some algae, and some cyanobacteria.
One of the major phycobiliproteins in cyanobacteria is phycocyanins, and its chromophore is called phycocyanobilin. There are two stereoisomers of phycocyanobilin, but apparently only (2R,3Z)-phycocyanobilin is produced initially, with the second isomer potentially produced by a distinct bilin isomerase [Beale91].
(2R,3Z)-phycocyanobilin is biosynthesized from heme in a pathway that begins with the opening of the tetrapyrrole macrocycle of protoheme to form biliverdin-IX-α, in a reaction catalyzed by heme oxygenase 1 [Cornejo98].
In at least some cyanobacteria, such as Synechocystis sp. PCC 6803, biliverdin-IX-α is converted to (2R,3Z)-phycocyanobilin by a single enzyme, phycocyanobilin:ferredoxin oxidoreductase, encoded by the pcyA gene [Frankenberg01].
Beale91: Beale SI, Cornejo J (1991). "Biosynthesis of phycobilins. 3(Z)-phycoerythrobilin and 3(Z)-phycocyanobilin are intermediates in the formation of 3(E)-phycocyanobilin from biliverdin IX alpha." J Biol Chem 266(33);22333-40. PMID: 1939256
Brown89: Brown SB, Holroyd JA, Vernon DI, Shim YK, Smith KM (1989). "The biosynthesis of the chromophore of phycocyanin. Pathway of reduction of biliverdin to phycocyanobilin." Biochem J 261(1);259-63. PMID: 2505754
Cornejo92: Cornejo J, Beale SI, Terry MJ, Lagarias JC (1992). "Phytochrome assembly. The structure and biological activity of 2(R),3(E)-phytochromobilin derived from phycobiliproteins." J Biol Chem 267(21);14790-8. PMID: 1634523
Cornejo98: Cornejo J, Willows RD, Beale SI (1998). "Phytobilin biosynthesis: cloning and expression of a gene encoding soluble ferredoxin-dependent heme oxygenase from Synechocystis sp. PCC 6803." Plant J 15(1);99-107. PMID: 9744099
Frankenberg01: Frankenberg N, Mukougawa K, Kohchi T, Lagarias JC (2001). "Functional genomic analysis of the HY2 family of ferredoxin-dependent bilin reductases from oxygenic photosynthetic organisms." Plant Cell 13(4);965-78. PMID: 11283349
Emborg06: Emborg TJ, Walker JM, Noh B, Vierstra RD (2006). "Multiple heme oxygenase family members contribute to the biosynthesis of the phytochrome chromophore in Arabidopsis." Plant Physiol 140(3);856-68. PMID: 16428602
Gisk10: Gisk B, Yasui Y, Kohchi T, Frankenberg-Dinkel N (2010). "Characterization of the haem oxygenase protein family in Arabidopsis thaliana reveals a diversity of functions." Biochem J 425(2);425-34. PMID: 19860740
Kaneko95: Kaneko T, Tanaka A, Sato S, Kotani H, Sazuka T, Miyajima N, Sugiura M, Tabata S (1995). "Sequence analysis of the genome of the unicellular cyanobacterium Synechocystis sp. strain PCC6803. I. Sequence features in the 1 Mb region from map positions 64% to 92% of the genome." DNA Res 2(4);153-66, 191-8. PMID: 8590279
Kaneko96: Kaneko T, Sato S, Kotani H, Tanaka A, Asamizu E, Nakamura Y, Miyajima N, Hirosawa M, Sugiura M, Sasamoto S, Kimura T, Hosouchi T, Matsuno A, Muraki A, Nakazaki N, Naruo K, Okumura S, Shimpo S, Takeuchi C, Wada T, Watanabe A, Yamada M, Yasuda M, Tabata S (1996). "Sequence analysis of the genome of the unicellular cyanobacterium Synechocystis sp. strain PCC6803. II. Sequence determination of the entire genome and assignment of potential protein-coding regions." DNA Res 1996;3(3);109-36. PMID: 8905231
Park06: Park YJ, Yoo CB, Choi SY, Lee HB (2006). "Purifications and characterizations of a ferredoxin and its related 2-oxoacid:ferredoxin oxidoreductase from the hyperthermophilic archaeon, Sulfolobus solfataricus P1." J Biochem Mol Biol 39(1);46-54. PMID: 16466637
Willows00: Willows RD, Mayer SM, Foulk MS, DeLong A, Hanson K, Chory J, Beale SI (2000). "Phytobilin biosynthesis: the Synechocystis sp. PCC 6803 heme oxygenase-encoding ho1 gene complements a phytochrome-deficient Arabidopsis thalianna hy1 mutant." Plant Mol Biol 43(1);113-20. PMID: 10949378
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