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 | 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 | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
biliverdin Ixalpha + reduced ferredoxin | Synechocystis sp. | - |
(3Z)-phycocyanobilin + oxidized ferredoxin | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Synechocystis sp. | Q55891 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
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 | Comment | Organism |
---|---|---|
PcyA | a member of the ferredoxin-dependent bilin reductase family | Synechocystis sp. |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8.5 | - |
assay at | Synechocystis sp. |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
Ferredoxin | recombinantly expressed in Escherichia coli strains C41(DE3) | Synechocystis sp. |
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. |