title: Catalytic coupling of the active sites in acetyl-CoA synthase, a bifunctional CO-channeling enzyme.
abstract: Acetogenic bacteria contain acetyl-CoA synthase (ACS), an enzyme with two distinct nickel-iron-sulfur active sites connected by a tunnel through which CO migrates. One site reduces CO2 to CO, while the other synthesizes acetyl-CoA from CO, CoA, and the methyl group of another protein (CH3-CP). Rapid binding of CO2 and a two-electron reduction activates ACS. When CoA and CH3-CP bind ACS, CO is rerouted through the tunnel to the synthase site, and kinetic parameters at the reductase site are altered. Under these conditions, the rates of CO2 reduction and acetyl-CoA synthesis are synchronized by an ordered catalytic mechanism.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Maynard
authors.forename: P A
authors.initials: PA
authors.lastname: Lindahl
mesh_terms: D000106:Acetate-CoA Ligase / Q000737:chemistry / Q000378:metabolism*; D000105:Acetyl Coenzyme A / Q000737:chemistry; D000445:Aldehyde Oxidoreductases; D001665:Binding Sites; D002245:Carbon Dioxide / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism*; D002384:Catalysis; D003013:Clostridium / Q000201:enzymology; D004789:Enzyme Activation; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D007700:Kinetics; D008667:Metalloproteins / Q000378:metabolism; D008956:Models, Chemical; D009097:Multienzyme Complexes; D009532:Nickel
chemical_list: D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D009097:Multienzyme Complexes; D002245:Carbon Dioxide; D000105:Acetyl Coenzyme A; D009532:Nickel; D002248:Carbon Monoxide; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase; D000106:Acetate-CoA Ligase