Stuchebrukhov research group           Department of Chemistry           University of California at Davis

One of the most interesting biochemical systems where coupled ET and PT reactions play the role is cytochrome c oxidase (CcO). This membrane-bound protein is the terminal enzyme of the cell respiratory electron-transport chain in mitochondria and aerobic bacteria.

CcO uses electrons and protons to catalyse the reduction of O2 to H2O and utilize the free energy of the reduction reaction for a proton pumping across the inner-mitochondrial membrane, a process which results in a generation of a membrane electrochemical proton gradient.

The energy stored by the gradient subsequently drives synthesis of adenosine triphosphate (ATP), the key molecule in intracellular energy transfer involved in converting food into energy.

Mitochondrion - Powerhouse of the cell

The crystal structure of CcO has been solved for several organisms, but the mechanism of how electrons and protons are coupled in the enzyme is still an ongoing unsolved problem. In our work of past few years, we proposed the mechanism of proton pumping of this enzyme, which is presented here.

Computational Methods

Dielectric Models

CcO Project

Electrostatic Potential of CcO

Water in Catalytic Site

Proposed Proton Pumping Mechanism

Proton Exit Pathway

Conformational Changes of Glu242

Improved DFT/Electrostatic pKa Calculations



C&EN Report On The Symposium: Five Decades Of Marcus Theories