1. Chemistry Department, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
2. Institute of Molecular Systems Biology, Department of Health Sciences and Technology, ETH Zurich, Auguste-Piccard-Hof 1, 8093 Zurich, Switzerland
3. Functional Genomics Center Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
4. Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States