1. Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216, United States
2. NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Building 436E, Argonne National Laboratory, Argonne, Illinois 60439, United States
3. Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
4. Department of Chemistry, Georgia State University, Atlanta, Georgia 30302, United States