title: A cytochrome C oxidase model catalyzes oxygen to water reduction under rate-limiting electron flux.
abstract: We studied the selectivity of a functional model of cytochrome c oxidase's active site that mimics the coordination environment and relative locations of Fe(a3), Cu(B), and Tyr(244). To control electron flux, we covalently attached this model and analogs lacking copper and phenol onto self-assembled monolayer-coated gold electrodes. When the electron transfer rate was made rate limiting, both copper and phenol were required to enhance selective reduction of oxygen to water. This finding supports the hypothesis that, during steady-state turnover, the primary role of these redox centers is to rapidly provide all the electrons needed to reduce oxygen by four electrons, thus preventing the release of toxic partially reduced oxygen species.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. jpc@stanford.edu
authors.forename: James P
authors.initials: JP
authors.lastname: Collman
authors.forename: Neal K
authors.initials: NK
authors.lastname: Devaraj
authors.forename: Richard A
authors.initials: RA
authors.lastname: Decréau
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.forename: Yi-Long
authors.initials: YL
authors.lastname: Yan
authors.forename: Wataru
authors.initials: W
authors.lastname: Ebina
authors.forename: Todd A
authors.initials: TA
authors.lastname: Eberspacher
authors.forename: Christopher E D
authors.initials: CE
authors.lastname: Chidsey
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D003300:Copper; D004563:Electrochemistry; D004566:Electrodes; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D004583:Electrons; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D019800:Phenol / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water; D019800:Phenol; D014443:Tyrosine; D003300:Copper; D007501:Iron; D003576:Electron Transport Complex IV; D010100:Oxygen