Pyruvate Ferredoxin Oxidoreductase from the Hyperthermophilic
Proc. Natl. Acad. Sci. USA Vol. 94, pp. 9608–9613, September 1997 Biochemistry Pyruvate ferredoxin oxidoreductase from the hyperthermophilic archaeon, Pyrococcus furiosus, functions as a CoA-dependent pyruvate decarboxylase (archaeayaldehydeydecarboxylationy2-keto acidythiamine pyrophosphate) KESEN MA*, ANDREA HUTCHINS*, SHI-JEAN S. SUNG†, AND MICHAEL W. W. ADAMS*‡ *Center for Metalloenzyme Studies, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602; and †Institute of Tree Root Biology, U.S. Department of Agriculture–Forest Service, Athens, GA 30602 Communicated by Gregory A. Petsko, Brandeis University, Waltham, MA, June 17, 1997 (received for review June 1, 1996) ABSTRACT Pyruvate ferredoxin oxidoreductase (POR) hyperthermophilic archaea and these are involved in peptide has been previously purified from the hyperthermophilic fermentation. They use 2-ketoglutarate (KGOR) (11), in- archaeon, Pyrococcus furiosus, an organism that grows opti- dolepyruvate (IOR) (12), and 2-ketoisovalerate (VOR) (13) as mally at 100°C by fermenting carbohydrates and peptides. The substrates, and function to oxidatively decarboxylate the 2- enzyme contains thiamine pyrophosphate and catalyzes the keto acids generated by the transamination of glutamate, oxidative decarboxylation of pyruvate to acetyl-CoA and CO2 aromatic amino acids, and branched chain amino acids, re- and reduces P. furiosus ferredoxin. Here we show that this spectively, to the corresponding CoA derivative (13). enzyme also catalyzes the formation of acetaldehyde from The growth of hyperthermophilic archaea such as P. furiosus pyruvate in a CoA-dependent reaction. Desulfocoenzyme A is also unusual in that it is dependent upon tungsten (14), a substituted for CoA showing that the cofactor plays a struc- metal seldom used in biological systems (15).
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