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Isolation of an enzyme complex with carbon monoxide dehydrogenase activity containing corrinoid and nickel from acetate-growth Methanosarcina thermophila

Journal Article · · J. Bacteriol.; (United States)
OSTI ID:7119768

Fast protein liquid chromatography of cell extract from methanol- or acetate-grown Methanoscarcina thermophila resolved two peaks of CO dehydrogenase activity. The activity of one of the CO dehydrogenases was sixfold greater in acetate-grown compared with methanol-grown cells. This CO dehydrogenase was purified to apparent homogeneity (70 ..mu..mol of methyl viologen reduced per min per mg of protein) and made up greater than 10% of the cellular protein of acetate-grown cells. The native enzyme (M/sub r/ 250,000) formed aggregates with an M/sub r/ of approximately 1,000,000. The enzyme contained five subunits (M/sub r/s 89,000, 71,000, 60,000, 58,000, and 19,000), suggesting a multifunctional enzyme complex. Nickel, iron, cobalt, zinc, inorganic sulfide, and a corrinoid were present in the complex. The UV-visible spectrum suggested the presence of iron-sulfur centers. The electron paramagnetic resonance spectrum contained g values of 2.073, 2.049, and 2.028; these features were broadened in enzyme that was purified from cells grown in the presence of medium enriched with /sup 61/Ni, indicating the involvement of this metal in the spectrum. The pattern of potassium cyanide inhibition indicated that cyanide binds at or near the CO binding site. The properties of the enzyme imply an involvement in the dissimilation of acetate to methane, possibly by cleavage of acetate or activated acetate.

Research Organization:
Virginia Polytechnic Institute and State Univ., Blacksburg
OSTI ID:
7119768
Journal Information:
J. Bacteriol.; (United States), Journal Name: J. Bacteriol.; (United States) Vol. 168:3; ISSN JOBAA
Country of Publication:
United States
Language:
English