Proton-transport mechanisms in cytochrome c oxidase revealed by studies of kinetic isotope effects.

ABSTRACT: Cytochrome c oxidase (CytcO) is a membrane-bound enzyme, which catalyzes the reduction of di-oxygen to water and uses a major part of the free energy released in this reaction to pump protons across the membrane. In the Rhodobacter sphaeroides aa₃ CytcO all protons that are pumped across the membrane, as well as one half of the protons that are used for O₂ reduction, are transferred through one specific intraprotein proton pathway, which holds a highly conserved Glu286 residue. Key questions that need to be addressed in order to understand the function of CytcO at a molecular level are related to the timing of proton transfers from Glu286 to a "pump site" and the catalytic site, respectively. Here, we have investigated the temperature dependencies of the H/D kinetic-isotope effects of intr

SUBMITTER: Johansson AL 

PROVIDER: S-EPMC3139697 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature