1. Department of Chemistry, University of Wisconsin−Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
2. School of Medicine, Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
3. School of Pharmacy, University of Wisconsin−Madison, 777 Highland Avenue, Madison, Wisconsin 53705, United States