Department of Physics and Astronomy, University of Southern California, Los Angeles, California, United States of America.|Department of Biological Sciences, Centre for Molecular Simulations, University of Calgary, Calgary, Alberta, Canada.|Department of Physics and Astronomy, University of Southern California, Los Angeles, California, United States of America.|Department of Biological Sciences, Centre for Molecular Simulations, University of Calgary, Calgary, Alberta, Canada.|Department of Physiology and Biophysics, and Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America.