1. Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany;, ,
2. Current affiliation: Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland;
3. Current affiliation: ZIK HALOmem, Martin Luther University of Halle-Wittenberg, 06120 Halle (Saale), Germany
4. Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
5. Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany