1 Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
2 Department of Chemistry and Chemical Biology, Rutgers University, New Brunswick, New Jersey 08854, USA.
3 Computational Multiscale Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1316, USA.
4 Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA.
5 Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
6 NIH Center for Macromolecular Modeling and Bioinformatics, Theoretical and Computational Biophysics Group, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.