1. Department of Molecular Biology and Biochemistry, ‡Department of Pharmaceutical
Sciences, and §Department of
Chemistry, University of California, Irvine, California 92697-3900, United States
2. Departments of Chemistry and Molecular Biosciences, ⊥Chemistry of Life
Processes Institute, and #Center for Molecular
Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208-3113, United States