1. Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario N1G 2W1, Canada
2. Freie Universität Berlin, Physics Department, Theoretical Molecular Biophysics Group, D-14195 Berlin, Germany
3. University of Bucharest, Faculty of Physics, Măgurele 077125, Romania
4. Forschungszentrum Jülich, Institute for Computational Biomedicine (IAS-5/INM-9), 52428 Jülich, Germany