1KEK

Crystal Structure of the Free Radical Intermediate of Pyruvate:Ferredoxin Oxidoreductase

Summary for 1KEK

• Entry DOI: 10.2210/pdb1kek/pdb
• Related: 1B0P 2PDA
• Descriptor: Pyruvate-Ferredoxin Oxidoreductase, MAGNESIUM ION, CALCIUM ION, ... (7 entities in total)
• Functional Keywords: homodimer, 7 domains, oxidoreductase
• Biological source: Desulfovibrio africanus
• Total number of polymer chains: 2
• Total formula weight: 270669.14

Authors

Chabriere, E.,Vernede, X.,Guigliarelli, B.,Charon, M.-H.,Hatchikian, E.C.,Fontecilla-Camps, J.C. (deposition date: 2001-11-16, release date: 2001-12-21, Last modification date: 2024-10-16)

Primary citation

Chabriere, E.,Vernede, X.,Guigliarelli, B.,Charon, M.H.,Hatchikian, E.C.,Fontecilla-Camps, J.C.
Crystal structure of the free radical intermediate of pyruvate:ferredoxin oxidoreductase.
Science, 294:2559-2563, 2001

PubMed Abstract: 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.

PubMed: 11752578
DOI: 10.1126/science.1066198

Experimental method

X-RAY DIFFRACTION (1.9 Å)