1. Department of Chemistry, Vanderbilt University, Nashville, Tennessee37235, United States
2. Center for Structural Biology, Vanderbilt University, Nashville, Tennessee37240, United States
3. Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee37240, United States
4. Department of Pharmacology, Vanderbilt University, Nashville, Tennessee37240, United States
5. Institute of Drug Discovery, Faculty of Medicine, University of Leipzig, 04103Leipzig, Germany