1kek | pdb_00001kek
Crystal Structure of the Free Radical Intermediate of Pyruvate:Ferredoxin Oxidoreductase
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Overview
In anaerobic organisms, the decarboxylation of pyruvate, a crucial component of intermediary metabolism, is catalyzed by the metalloenzyme pyruvate: ferredoxin oxidoreductase (PFOR) resulting in the generation of low potential electrons and the subsequent acetylation of coenzyme A (CoA). PFOR is the only enzyme for which a stable acetyl thiamine diphosphate (ThDP)-based free radical reaction intermediate has been identified. The 1.87 A-resolution structure of the radical form of PFOR from Desulfovibrio africanus shows that, despite currently accepted ideas, the thiazole ring of the ThDP cofactor is markedly bent, indicating a drastic reduction of its aromaticity. In addition, the bond connecting the acetyl group to ThDP is unusually long, probably of the one-electron type already described for several cation radicals but not yet found in a biological system. Taken together, our data, along with evidence from the literature, suggest that acetyl-CoA synthesis by PFOR proceeds via a condensation mechanism involving acetyl (PFOR-based) and thiyl (CoA-based) radicals.
About this Structure
1KEK is a Single protein structure of sequence from Desulfovibrio africanus with MG, CA, SF4, HTL and CO2 as ligands. Active as Pyruvate synthase, with EC number 1.2.7.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of the free radical intermediate of pyruvate:ferredoxin oxidoreductase., Chabriere E, Vernede X, Guigliarelli B, Charon MH, Hatchikian EC, Fontecilla-Camps JC, Science. 2001 Dec 21;294(5551):2559-63. PMID:11752578
Page seeded by OCA on Thu Feb 21 13:33:16 2008
