Surface-mediated proton-transfer reactions in membrane-bound proteins

As Outlined by Peter Mitchell in the chemiosmotic theory, an intermediate in energy conversion in biological systems is a proton electrochemical potential difference (proton gradient) across a membrane, generated by membrane-bound protein complexes. These protein complexes accommodate proton-transfer pathways through which protons are conducted. In this review, we focus specifically on the role of the protein-membrane surface and the surface-bulk water interface in the dynamics of proton delivery to these proton-transfer pathways. The general mechanisms are illustrated by experimental results from studies of bacterial photosynthetic reaction centres (RCs) and cytochrome e oxidase (CcO). (C) 2004 Elsevier B.V. All rights reserved.