1. Biomedical Research Foundation, Academy of Athens, 11527 Athens, Greece
2. Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana−Champaign, Unité Mixte de Recherche n◦7019, Université de Lorraine, B.P. 70239, 54506 Vandœuvre-lès-Nancy Cedex, France
3. Department of Biochemistry and Molecular Biology, The University of Chicago, 929 East 57th Street W225, Chicago, Illinois 60637, United States
4. Theoretical and Computational Biophysics Group, Beckman Institute, and Department of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States