Electron Transfer Reactions Between Cytochrome c, Cytochrome c Oxidase and Dioxygen

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This research, supported by the Analytical and Surface Chemistry Program in the Chemistry Division, will study electron transfer thermodynamics, kinetics, and mechanisms of enzyme action for cytochrome c oxidase. The enzyme will be adsorbed to a gold electrode and embedded in a lipid bilayer. Through both electrochemical and spectroscopic measurements (including magnetic circular dichroism) the electrical and structural dynamics of oxidation/reduction processes will be studied. The use of lipid bilayers will keep enzyme subunits from clustering at the electrode surface, improving the likelihood that the dynamics observed correspond to the specific units desired rather than to agglomorates. %%% Cytochrome c is a ubiquitous biological transfer agent. The efficiency of respiration and photosynthesis are largely dependent on the dynamics of electron transfer between cytochrome c and two enzymes: cytochrome c oxidase and cytochrome c reductase. This research will study the electron transfer dynamics by adsorbing cytochrome c reductase on a gold electrode, otherwise covered by a lipid bilayer to emulate a cell membrane. The goal of the work is to observe conformation changes in the enzyme as a result of electron transfer; such changes are hypothesized to be an essential feature of efficient biological electron transfer processes.