1. Department of Pharmaceutical Chemistry, School of Pharmacy, 926 Medical Sciences Building, University of California, San Francisco, California 94143-0446, Stanford Synchrotron Radiation Laboratory, Stanford, California 94309, Department of Biochemistry and Biophysics, University of California, San Francisco, California 94143-0448, Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah 84132, and Department of Biochemistry, University of Utah School of Medicine, 50 North...