1. Center for the Science of Therapeutics, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts 02142, United States
2. Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, United States
3. Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
4. Howard Hughes Medical Institute, Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts 02142, United States