1. Department of ChemistryLudwig-Maximilians-Universität München and Munich Center for Integrated Protein Science Butenandtstrasse 5–13 81377 München Germany
2. Present address: Department of Chemical BiologyMax Planck Institute for Medical Research Jahnstr. 29 69120 Heidelberg Germany
3. Present address: Department of Chemical BiologyForschungsinstitut für Molekulare Pharmakologie Robert-Rössle Str. 10 13125 Berlin Germany
4. CNRS UMR 8576University of Lille Villeneuve d'Asq France
5. Univ. LilleCNRSInserm, CHU LilleInstitut Pasteur de LilleU1019—UMR 8204, Center for Infection and Immunity of Lille (CIIL) 59000 Lille France
6. Department of Biochemistry and Molecular BiologyBoonshoft School of MedicineWright State University Dayton OH 45435 USA
7. Department of ChemistrySilver Center for Arts and ScienceNew York University 100 Washington Square East New York NY 10003 USA