1. Departments of Molecular Biology and Biochemistry, Pharmaceutical Sciences, and Chemistry, University of California, Irvine, California 92697-3900, United States
2. Department of Chemistry, Department of Molecular Biosciences, Center for Molecular Innovation and Drug Discovery, and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States