Demonstration of short-lived complexes of cytochrome c with cytochrome bc1 by EPR spectroscopy: implications for the mechanism of interprotein electron transfer.

ABSTRACT: One of the steps of a common pathway for biological energy conversion involves electron transfer between cytochrome c and cytochrome bc1. To clarify the mechanism of this reaction, we examined the structural association of those two proteins using the electron transfer-independent electron paramagnetic resonance (EPR) techniques. Drawing on the differences in the continuous wave EPR spectra and saturation recoveries of spin-labeled bacterial and mitochondrial cytochromes c recorded in the absence and presence of bacterial cytochrome bc1, we have exposed a time scale of dynamic equilibrium between the bound and the free state of cytochrome c at various ionic strengths. Our data show a successive decrease of the bound cytochrome c fraction as the ionic strength increases, with a limit of app

SUBMITTER: Sarewicz M 

PROVIDER: S-EPMC2529009 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature