"Proton transfer across and along biological membranes"

Seminar by Prof Peter Brzezinski

Department of Biochemistry and Biophysics , University of Stockholm

 Friday, May 24th – 13:30

Aud. 7, HCØ, Universitetsparken 5

 Abstract: Cytochrome c oxidase (CytcO) is a multisubunit membrane-bound enzyme, which catalyzes oxidation of four molecules of cytochrome c2+ and reduction of molecular oxygen to water. The electrons and protons are taken from opposite sides of the membrane such that the reaction results in a charge separation that is equivalent to moving one positive charge across the membrane for each electron transferred to O2.

In addition, part of the free energy available from the catalytic reaction is used to pump one proton across the membrane per electron transferred to O2. This pumping stoichiometry of 1 H+/e‑ can be modulated by introduction of single-site mutations, as far away as ~25 Å from the catalytic site, to obtain essentially any stoichiometry in the range 0-1. In many cases these mutations leave the intramolecular electron and proton-transfer rates unaffected. 

Understanding the molecular mechanism underlying the uncoupling of proton pumping from O2 reduction allowed us to propose a molecular design of the proton-pumping machinery in the respiratory oxidases.

Arranged by: Nikos Hatzakis hatzakis@nano.ku.dk and Dimitros Stamou - Stamou@nano.ku.dk