Citation

Dobbek H, Gremer L, Meyer O, Huber R. Proc. Natl. Acad. Sci. U. S. A. 1999; 96(16): 8884-8889.

Copyright

(Copyright © 1999, National Academy of Sciences)

DOI

10.1073/pnas.96.16.8884

PMID

unavailable

Abstract

CO dehydrogenase from the aerobic bacterium Oligotropha carboxidovorans catalyzes the oxidation of CO with H2O, yielding CO2, two electrons, and two H+. Its crystal structure in the air-oxidized form has been determined to 2.2 Å. The active site of the enzyme, which contains molybdenum with three oxygen ligands, molybdopterin-cytosine dinucleotide and S-selanylcysteine, delivers the electrons to an intramolecular electron transport chain composed of two types of [2Fe-2S] clusters and flavin-adenine dinucleotide. CO dehydrogenase is composed of an 88.7-kDa molybdoprotein (L), a 30.2-kDa flavoprotein (M), and a 17.8-kDa iron-sulfur protein (S). It is organized as a dimer of LMS heterotrimers and resembles xanthine dehydrogenase/oxidase in many, but not all, aspects. A mechanism based on a structure with the bound suicide-substrate cyanide is suggested and displays the necessity of S-selanylcysteine for the catalyzed reaction.

Language: en

Keywords

aerobic bacterium; article; Bacteria (microorganisms); carbon monoxide dehydrogenase; catalysis; crystal structure; cysteine derivative; electron; electron transport; enzyme active site; enzyme mechanism; flavine adenine nucleotide; iron sulfur protein; nonhuman; Oligotropha carboxidovorans; oxidation; priority journal; xanthine dehydrogenase; xanthine oxidase