Literature summary for 1.3.7.5 extracted from

Hagiwara, Y.; Sugishima, M.; Khawn, H.; Kinoshita, H.; Inomata, K.; Shang, L.; Lagarias, J.C.; Takahashi, Y.; Fukuyama, K.
Structural insights into vinyl reduction regiospecificity of phycocyanobilin:ferredoxin oxidoreductase (PcyA) (2010), J. Biol. Chem., 285, 1000-1007.

Crystallization (Commentary)

Crystallization (Comment)	Organism
purified recombinant wild-type PcyA and PcyA-E76Q mutant in complex with 18EtBV or biloverdin IXalpha and biliverdin XIIIalpha, hanging drop vapor diffusion method, 20°C, method optimization, protein solution containing wild-type PcyA or mutant E76Q and bilin is mixed with reservoir solutions containing 0.85 M sodium citrate, 0.1 M sodium cacodylate, pH 7.0, for the PcyA-18EtBV complex and 2.0 M ammonium sulfate, 0.2 M NaCl, and 0.1M sodium cacodylate, pH7.0, for the PcyA-BV13 complex, for the mutant a reservoir solution containing 1.7 M ammonium sulfate, 2% PEG 400, and 0.1 M HEPES, pH 7.0, is used, X-ray diffraction structure determination and analysis at 1.04-1.48 A resolution	Synechocystis sp.

Crystallization (Comment)

Organism

purified recombinant wild-type PcyA and PcyA-E76Q mutant in complex with 18EtBV or biloverdin IXalpha and biliverdin XIIIalpha, hanging drop vapor diffusion method, 20°C, method optimization, protein solution containing wild-type PcyA or mutant E76Q and bilin is mixed with reservoir solutions containing 0.85 M sodium citrate, 0.1 M sodium cacodylate, pH 7.0, for the PcyA-18EtBV complex and 2.0 M ammonium sulfate, 0.2 M NaCl, and 0.1M sodium cacodylate, pH7.0, for the PcyA-BV13 complex, for the mutant a reservoir solution containing 1.7 M ammonium sulfate, 2% PEG 400, and 0.1 M HEPES, pH 7.0, is used, X-ray diffraction structure determination and analysis at 1.04-1.48 A resolution

Synechocystis sp.

Protein Variants

Protein Variants	Comment	Organism
E76Q	site-directed mutagenesis, substrate-binding structure compared to the wild-type enzyme. Overall folds and the binding sites of the U-shaped substrates of all three complexes are similar with wild-type PcyABV, the orientation of the Glu76 side chain, which is in close contact with the exo-vinyl group in PcyA-biliverdin IXalpha, is rotated away from the bilin D-ring. The local structures around the A-rings in the three complexes, which all retain the ability to reduce the A-ring of their bound pigments, are nearly identical with that of wild-type PcyA-biliverdin IXalpha	Synechocystis sp.

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
biliverdin Ixalpha + reduced ferredoxin	Synechocystis sp.	-	(3Z)-phycocyanobilin + oxidized ferredoxin	-	?

Organism

Organism	UniProt	Comment	Textmining
Synechocystis sp.	Q55891	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.
biliverdin Ixalpha + reduced ferredoxin	-	Synechocystis sp.	(3Z)-phycocyanobilin + oxidized ferredoxin	-	?
biliverdin Ixalpha + reduced ferredoxin	proton-donating role of the carboxylic acid side chain of residue Glu76 for exo-vinyl reduction, structural basis for the reduction regiospecificity of PcyA, overview	Synechocystis sp.	(3Z)-phycocyanobilin + oxidized ferredoxin	-	?
biliverdin XIIIalpha + reduced ferredoxin	a synthetic substrate that lacks an exo-vinyl group	Synechocystis sp.	? + oxidized ferredoxin	-	?

Synonyms

Synonyms	Comment	Organism
PcyA	a member of the ferredoxin-dependent bilin reductase family	Synechocystis sp.

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
8.5	-	assay at	Synechocystis sp.

Cofactor

Cofactor	Comment	Organism	Structure
Ferredoxin	recombinantly expressed in Escherichia coli strains C41(DE3)	Synechocystis sp.

General Information

General Information	Comment	Organism
physiological function	unlike other ferredoxin-dependent bilin reductases that catalyze a two-electron reduction, PcyA sequentially reduces D-ring (exo) and A-ring (endo) vinyl groups of biliverdin IXalpha to yield phycocyanobilin, a key pigment precursor of the light-harvesting antennae complexes of red algae, cyanobacteria, and cryptophytes	Synechocystis sp.