Increased Superoxide Production in the Cytochrome B6F Complex: A Function for the Enigmatic Chlorophyll-A (original) (raw)

wild-type RBS COX; however, the a-region of the reduced spectrum for E90H(SIII) displayed a slight red shift of the absorbance maximum by 1 nm, resembling that seen for the SIII-depleted oxidase. E90H(III) and E90H/ H212(III) mutant proteins were determined to contain stoichiometric amount of each subunit by SDS-PAGE gel, similar to wild-type COX. Electron transfer rates observed at pH 6.5, for E90H(III)/H212E(III) and E90H(SIII) COX, were decreased by 17 and 39% respectively, as compared to WT COX. The mutants exhibit little or no suicide inactivation when compared to the SIII-depleted RBS COX. pH dependence of electron transfer activity for E90H(III)/ H212E(III) and E90H(III) were also not altered when compared to WT enzyme. Proton pumping experiments on reconstituted E90H(III) and E90H(III)/ H212E(III) in liposomes will be discussed.