1. Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany, Department of Biochemistry and Molecular Biology II: Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistraβe 52, 20246 Hamburg, Germany, and Institute of Physical Chemistry and Electrochemistry, TU Dresden, Bergstraβe 66b, 01062 Dresden, Germany