1. Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, Germany
2. Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, Martinsried, Germany
3. Freiburg Institute for Advanced Studies, University of Freiburg, Albertstr. 19, Freiburg, Germany