1. Department
of Chemistry, Washington University in St. Louis, One Brookings
Drive, St. Louis, Missouri 63130, United States
2. Analytical
Research and Development, Pfizer Incorporated, Chesterfield, Missouri 63017, United States
3. Department
of Biochemistry and Molecular Biophysics, School of Medicine, Washington University in St. Louis, 660 South Euclid Avenue, St. Louis, Missouri 63110, United States