2g18

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">pcyA ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1167 Anabaena sp.])</td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Phycocyanobilin:ferredoxin_oxidoreductase Phycocyanobilin:ferredoxin oxidoreductase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.3.7.5 1.3.7.5] </span></td></tr>

[[https://www.uniprot.org/uniprot/PCYA_NOSS1 PCYA_NOSS1]] Catalyzes the four-electron reduction of biliverdin IX-alpha (2-electron reduction at both the A and D rings); the reaction proceeds via an isolatable 2-electron intermediate, 181,182-dihydrobiliverdin. Upon overexpression in E.coli with PCB:ferredoxin oxidoreductase, CpeS and either CpcB or PecB permits synthesis of phycocyanin-coupled CpcB or PecB.<ref>PMID:16452471</ref>

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== Publication Abstract from PubMed ==

The X-ray crystal structure of the substrate-free form of phycocyanobilin (PCB)-ferredoxin oxidoreductase (PcyA; EC 1.3.7.5) from the cyanobacterium Nostoc sp. PCC7120 has been solved at 2.5 A resolution. A comparative analysis of this structure with those recently reported for substrate-bound and substrate-free forms of PcyA from the cyanobacterium Synechocystis sp. PCC6803 (Hagiwara et al. (2006) Proc. Natl. Acad. Sci. U.S.A. 103, 27-32; Hagiwara et al. (2006) FEBS Lett. 580, 3823-3828) provides a compelling picture of substrate-induced changes in the PcyA enzyme and the chemical basis of PcyA's catalytic activity. On the basis of these structures and the biochemical analysis of site-directed mutants of Nostoc PcyA, including mutants reported in recent studies (Tu et al. (2006) J. Biol. Chem. 281, 3127-3136) as well as mutants described in this study, a revised mechanism for the PcyA-mediated four-electron reduction of biliverdin IXalpha to 3E/3Z-phycocyanobilin via enzyme-bound bilin radical intermediates is proposed. The mechanistic insight of these studies, along with homology modeling, have provided new insight into the catalytic mechanisms of other members of the ferredoxin-dependent bilin reductase family that are widespread in oxygenic photosynthetic organisms.

Insight into the radical mechanism of phycocyanobilin-ferredoxin oxidoreductase (PcyA) revealed by X-ray crystallography and biochemical measurements.,Tu SL, Rockwell NC, Lagarias JC, Fisher AJ Biochemistry. 2007 Feb 13;46(6):1484-94. Epub 2007 Jan 17. PMID:17279614<ref>PMID:17279614</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 2g18" style="background-color:#fffaf0;"></div>

[[Category: Fisher, A J]]

[[Category: Lagarias, J C]]

[[Category: Tu, S L]]

[[Category: Oxidoreductase]]