Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America.|Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America.|Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America, Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America, Howard Hughes Medical Institute, University of California San Diego, La Jolla, California, United States of America, National Biomedical Computation Resource, University of California San Diego, La Jolla, California, United States of America.