1. Department of Chemistry, Biophysical Chemistry (PC III), Bielefeld University, 33615 Bielefeld, Germany, MaxPlanck Institute of Molecular Physiology, 44221 Dortmund, Germany, Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany, and Japan Science and Technology Agency, 102-0075, Tokyo, Japan