1. Laboratoire de Chimie Physique, CNRS, Faculté d'Orsay, Orsay/UMR 8000, University of Paris XI, 91405 Cedex, France, Department of Biophysics, University of Szeged, H-6722, Szeged, Hungary, Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, D-60438 Frankfurt/Main, Germany, and Laboratoire de Bioénergétique Cellulaire UMR 6191, DEVM, CEA/Cadarache, CNRS-CEA-Aix-Marseille II, 13108 Saint Paul lez Durance Cedex, France