1. National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
2. University of Chinese Academy of Sciences Beijing 100101 China
3. Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Strasse 3 60438 Frankfurt am Main Germany
4. Institute of Physical and Theoretical Chemistry Goethe University Max-von Laue-Strasse 7 60438 Frankfurt am Main Germany