1. Laboratoire des Proteines Complexes, Universite de Tours, 2 bis Boulevard Tonnelle, F-37032 Tours, France
2. European Molecular Biology Laboratory, Meyerhofstrasse 1, Postfach 1022.09, D-69012 Heidelberg, Germany
3. Department of Physics of Complex Systems, Eotvos University, Pazmany Peter setany 1/A, H-1117 Budapest, Hungary
4. HLRZ, Forschungszentrum Julich, D-52425 Julich, Germany
5. Condensed Matter Physics and Chemistry Department, Riso National Laboratory, DK-4000 Roskilde, Denmark
6. The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O, Denmark