1. Institute of Molecular Biology & Biophysics, ETH Zurich, Otto-Stern-Weg 5, CH-8093 Zurich, Switzerland
2. Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
3. Bioorganische Chemie, University of Bayreuth, D-95440 Bayreuth, Germany
4. Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, CH-4056 Basel, Switzerland