title: A methylnickel intermediate in a bimetallic mechanism of acetyl-coenzyme A synthesis by anaerobic bacteria.
abstract: Resonance Raman (RR) spectroscopy was used to identify a methylnickel adduct (upsilon Ni-C = 422 wave numbers) of carbon monoxide dehydrogenase (CODH) from Clostridium thermoaceticum. Formed at a nickel/iron-sulfur cluster on CODH called center A, the methylnickel species is the precursor of the methyl group of acetyl-coenzyme A in an anaerobic pathway of carbon monoxide or carbon dioxide fixation. Rapid kinetic and RR studies demonstrated that methylation of nickel occurs by heterolysis of the methyl-cobalt bond (upsilon Co-C = 429 wave numbers) of a methylated corrinoid/iron-sulfur protein. In combination with the earlier finding of an iron-carbonyl adduct at center A, detection of the methylnickel intermediate establishes a bimetallic mechanism for acetyl-coenzyme A synthesis.
authors.affiliation: Department of Biochemistry, Beadle Center, University of Nebraska, Lincoln 68588-0664, USA.
authors.forename: M
authors.initials: M
authors.lastname: Kumar
authors.forename: D
authors.initials: D
authors.lastname: Qiu
authors.forename: T G
authors.initials: TG
authors.lastname: Spiro
authors.forename: S W
authors.initials: SW
authors.lastname: Ragsdale
mesh_terms: D000105:Acetyl Coenzyme A / Q000096:biosynthesis*; D000445:Aldehyde Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D000693:Anaerobiosis; D002244:Carbon / Q000737:chemistry / Q000378:metabolism; D002248:Carbon Monoxide / Q000378:metabolism; D003013:Clostridium / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D008667:Metalloproteins / Q000737:chemistry / Q000378:metabolism*; D008745:Methylation; D009097:Multienzyme Complexes; D009532:Nickel / Q000378:metabolism*; D013059:Spectrum Analysis, Raman
chemical_list: D007506:Iron-Sulfur Proteins; D008667:Metalloproteins; D009097:Multienzyme Complexes; D000105:Acetyl Coenzyme A; D002244:Carbon; D009532:Nickel; D002248:Carbon Monoxide; D007501:Iron; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase