1. Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot 76100, Israel
2. Institute for Advanced Study (IAS) and Center of Integrated Protein Science, Department of Chemistry, Technical University of Munich, 85747 Garching, Germany
3. Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany