1. Reaction Biology Corporation, One Great Valley Parkway, Malvern, Pennsylvania 19355, United States
2. Department of Molecular and Cellular Pharmacology, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida 33136, United States
3. Crystallography Core Facility, Scripps Research, 130 Scripps Way, Jupiter, Florida 33458, United States;
4. Department of Biological Chemistry & Pharmacology, Ohio State University College of Medicine, Columbus, Ohio 43210, United States;