1. Center for Development of Therapeutics Broad Institute of MIT and Harvard Cambridge MA 02142 USA
2. Biophysics Program and Institute for Physical Science and Technology University of Maryland College Park MD 20742 USA
3. Department of Pharmacological Sciences Stony Brook University Stony Brook NY 11794-8651 USA
4. Department of Chemistry and Biochemistry and Institute for Physical Science and Technology University of Maryland College Park MD 20742 USA