Exploring the proton pump mechanism of cytochrome c oxidase in real time.

ABSTRACT: Cytochrome c oxidase catalyzes most of the biological oxygen consumption on Earth, a process responsible for energy supply in aerobic organisms. This remarkable membrane-bound enzyme also converts free energy from O(2) reduction to an electrochemical proton gradient by functioning as a redox-linked proton pump. Although the structures of several oxidases are known, the molecular mechanism of redox-linked proton translocation has remained elusive. Here, correlated internal electron and proton transfer reactions were tracked in real time by spectroscopic and electrometric techniques after laser-activated electron injection into the oxidized enzyme. The observed kinetics establish the long-sought reaction sequence of the proton pump mechanism and describe some of its thermodynamic properties.

SUBMITTER: Belevich I 

PROVIDER: S-EPMC1796784 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature