1. IMETUM, Physics Department, CeNS and CIPSM, Technische Universität München, 85748 Garching, Germany, Key Laboratory for Computational Biology, MPG-CAS Partner Institute for Computational Biology, Chinese Academy of Sciences, 200031 Shanghai, China, Bioquant, Heidelberg University, 69120 Heidelberg, Germany, and Center for Nanoscience and Department of Physics, University of Munich, 80799 Munich, Germany