1. Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
2. Laboratory of Single Molecule Biophysics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20982, United States
3. Departments of Biochemistry and Medicine (Hematology/Oncology), Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
4. VA Tennessee Valley Healthcare System, Nashville, Tennessee 37212, United States