1. CNRS, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France, CEA, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France, and Université Grenoble 1, Institut de Biologie Structurale Jean-Pierre Ebel, Grenoble, France
2. Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, B-1050 Bruxelles, Belgium
3. Molecular and Cellular Biology, Belgian Center for Nuclear Energy, SCK·CEN, B-2400 Mol, Belgium