title: Differential reduction of CO₂ by molybdenum and vanadium nitrogenases.
abstract: The molybdenum and vanadium nitrogenases are two homologous enzymes with distinct structural and catalytic features. Previously, it was demonstrated that the V nitrogenase was nearly 700 times more active than its Mo counterpart in reducing CO to hydrocarbons. Herein, a similar discrepancy between the two nitrogenases in the reduction of CO2 is reported, with the V nitrogenase being capable of reducing CO2 to CO, CD4, C2D4, and C2D6, and its Mo counterpart only capable of reducing CO2 to CO. Furthermore, it is shown that the V nitrogenase may direct the formation of CD4 in part via CO2-derived CO, but that it does not catalyze the formation of C2D4 and C2D6 along this route. The exciting observation of a V nitrogenase-catalyzed C-C coupling with CO2 as the origin of the building blocks adds another interesting reaction to the catalytic repertoire of this unique enzyme system. The differential activities of the V and Mo nitrogenases in CO2 reduction provide an important framework for systematic investigations of this reaction in the future.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California, Irvine (USA).
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Rebelein
authors.forename: Yilin
authors.initials: Y
authors.lastname: Hu
authors.forename: Markus W
authors.initials: MW
authors.lastname: Ribbe
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D009591:Nitrogenase / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D002245:Carbon Dioxide; D008982:Molybdenum; D009591:Nitrogenase
keywords: CC coupling; carbon dioxide; carbon monoxide; hydrocarbons; nitrogenase