1. Department of Pharmacology and Department of Chemistry & Biochemistry, University of California at San Diego, La Jolla, California 92093, United States
2. Howard
Hughes Medical Institute, University of California at San Diego, La Jolla, California 92093, United States
3. National
Biomedical Computation Resource, University of California at San Diego, La
Jolla, California 92093, United States
4. Department
of Chemistry, University of Illinois at Urbana-Champaign, 600
South Mathews Avenue, Urbana, Illinois 61801, United States