1. Department of Chemistry & Physics, Western Carolina University, Cullowhee, North Carolina 28723, United States
2. Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Graduate Group in Biophysics, University of California, Berkeley, Berkeley, California 94720, United States
4. Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States