title: Activation of N2O reduction by the fully reduced micro4-sulfide bridged tetranuclear Cu Z cluster in nitrous oxide reductase.
abstract: The tetranuclear CuZ cluster catalyzes the two-electron reduction of N2O to N2 and H2O in the enzyme nitrous oxide reductase. This study shows that the fully reduced 4CuI form of the cluster correlates with the catalytic activity of the enzyme. This is the first demonstration that the S = 1/2 form of CuZ can be further reduced. Complementary DFT calculations support the experimental findings and demonstrate that N2O binding in a bent mu-1,3-bridging mode to the 4CuI form is most efficient due to strong back-bonding from two reduced copper atoms. This back-donation activates N2O for electrophilic attack by a proton.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305, USA.
authors.forename: Somdatta
authors.initials: S
authors.lastname: Ghosh
authors.forename: Serge I
authors.initials: SI
authors.lastname: Gorelsky
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Inês
authors.initials: I
authors.lastname: Cabrito
authors.forename: José J G
authors.initials: JJ
authors.lastname: Moura
authors.forename: Isabel
authors.initials: I
authors.lastname: Moura
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
mesh_terms: D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation; D007700:Kinetics; D008958:Models, Molecular; D009609:Nitrous Oxide / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D013440:Sulfides; D003300:Copper; D010088:Oxidoreductases; C022763:nitrous oxide reductase; D009609:Nitrous Oxide