Spectroscopic Elucidation of a New Heme/Copper Dioxygen Structure Type: Implications for O⋅⋅⋅O Bond Rupture in Cytochrome c Oxidase

Authors


  • These studies were supported by the NIH (DK031450 to E.I.S., GM60353 to K.D.K., RR001209 to K.O.H.). M.T.K.-E. is supported by an NIH post-doctoral fellowship (GM085914). Computational resources were provided in part by the NSF through Teragrid (CHE080054N). Synchrotron resources were provided by the SSRL, the operation of which is supported by the DOE, Office of Basic Energy Science. The SSRL Structural Molecular Biology program is supported by the NIH (NCRR P41 RR001209) and the DOE Office of Biological and Environmental Research.

Abstract

original image

All's well that ends well: The geometric and electronic structure of the first end-on heme–peroxo–copper adduct (see picture) was elucidated using UV/Vis, resonance Raman, and X-ray absorption spectroscopy and is supported by DFT calculations. Coordination of the axial base is correlated to a spin-state change, leading to enhanced biomimetic reactivity, and gives insight into O[BOND]O bond cleavage by cytochrome c oxidase.

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