1. Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
2. Department of Biochemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02453, United States
3. Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, United States
4. Integrated Program for Biological and Genome Sciences, Department of Biochemistry and Biophysics, and Department of Microbiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States