1. Biophysics Group, Institute of Experimental Physics, Otto-von-Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany, Institute of Materials Chemistry, Vienna University of Technology, Veterinärplatz 1, A-1210 Vienna, Austria, and Department of Systems Biology, Max-Planck-Institute for Dynamics of Complex Technical Systems, Sandtorstrasse 1, 39106 Magdeburg, Germany