1. Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66047, United States
2. Department of Pharmacology, University of California at San Diego, La Jolla, California 92093, United States
3. San Diego Supercomputer Center, University of California at San Diego, La Jolla, California 92093, United States
4. Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093, United States
5. Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States