Spectral identification of intermediates generated during the reaction of dioxygen with the wild-type and EQ(I-286) mutant of Rhodobacter sphaeroides cytochrome c oxidase.

ABSTRACT: Cytochrome c oxidase from Rhodobacter sphaeroides is frequently used to model the more complex mitochondrial enzyme. The O(2) reduction in both enzymes is generally described by a unidirectional mechanism involving the sequential formation of the ferrous-oxy complex (compound A), the P(R) state, the oxyferryl F form, and the oxidized state. In this study we investigated the reaction of dioxygen with the wild-type reduced R. sphaeroides cytochrome oxidase and the EQ(I-286) mutant using the CO flow-flash technique. Singular value decomposition and multiexponential fitting of the time-resolved optical absorption difference spectra showed that three apparent lifetimes, 18 μs, 53 μs, and 1.3 ms, are sufficient to fit the kinetics of the O(2) reaction of the wild-type enzyme. A comparison of the

SUBMITTER: Szundi I 

PROVIDER: S-EPMC3532933 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature