A cytochrome C oxidase model catalyzes oxygen to water reduction under rate-limiting electron flux.
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.
Collman
James P
JP
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA. jpc@stanford.edu
Devaraj
Neal K
NK
Decréau
Richard A
RA
Yang
Ying
Y
Yan
Yi-Long
YL
Ebina
Wataru
W
Eberspacher
Todd A
TA
Chidsey
Christopher E D
CE
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*
D014867:Water; D019800:Phenol; D014443:Tyrosine; D003300:Copper; D007501:Iron; D003576:Electron Transport Complex IV; D010100:Oxygen