1 Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA. Electronic address: jeffrey.brender@mail.nih.gov.
2 Biophysics, Department of Chemistry, Biomedical Engineering, and Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI 48109-1055, USA.
3 Boston University School of Medicine, Department of Physiology & Biophysics, W302, 700 Albany St, Boston, MA 02118, USA.
4 Biomolecular NMR and Drug Design Laboratory, Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII (M), Kolkata 700054, India.