1. Laboratory
of Chemical Physics, National Institute of
Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
2. Department
of Chemistry, King’s College London, London SE1 1DB, United Kingdom
3. Laboratory
of Molecular Biology, National Institute
of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
4. Department
of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany