1ru3
Crystal Structure of the monomeric acetyl-CoA synthase from Carboxydothermus hydrogenoformans
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn anaerobic microorganisms employing the acetyl-CoA pathway, acetyl-CoA synthase (ACS) and CO dehydrogenase (CODH) form a complex (ACS/CODH) that catalyzes the synthesis of acetyl-CoA from CO, a methyl group, and CoA. Previously, a [4Fe-4S] cubane bridged to a copper-nickel binuclear site (active site cluster A of the ACS component) was identified in the ACS(Mt)/CODH(Mt) from Moorella thermoacetica whereas another study revealed a nickel-nickel site in the open form of ACS(Mt), and a zink-nickel site in the closed form. The ACS(Ch) of the hydrogenogenic bacterium Carboxydothermus hydrogenoformans was found to exist as an 82.2-kDa monomer as well as in a 1:1 molar complex with the 73.3-kDa CODHIII(Ch). Homogeneous ACS(Ch) and ACS(Ch)/CODHIII(Ch) catalyzed the exchange between [1-(14)C]acetyl-CoA and (12)CO with specific activities of 2.4 or 5.9 micromol of CO per min per mg, respectively, at 70 degrees C and pH 6.0. They also catalyzed the synthesis of acetyl-CoA from CO, methylcobalamin, corrinoid iron-sulfur protein, and CoA with specific activities of 0.14 or 0.91 micromol of acetyl-CoA formed per min per mg, respectively, at 70 degrees C and pH 7.3. The functional cluster A of ACS(Ch) contains a Ni-Ni-[4Fe-4S] site, in which the positions proximal and distal to the cubane are occupied by Ni ions. This result is apparent from a positive correlation of the Ni contents and negative correlations of the Cu or Zn contents with the acetyl-CoA/CO exchange activities of different preparations of monomeric ACS(Ch), a 2.2-A crystal structure of the dithionite-reduced monomer in an open conformation, and x-ray absorption spectroscopy. A functional Ni-Ni-[4Fe-4S] cluster in the monomeric acetyl-CoA synthase from Carboxydothermus hydrogenoformans.,Svetlitchnyi V, Dobbek H, Meyer-Klaucke W, Meins T, Thiele B, Romer P, Huber R, Meyer O Proc Natl Acad Sci U S A. 2004 Jan 13;101(2):446-51. Epub 2003 Dec 29. PMID:14699043[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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