1. Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA.
2. Department of Pathology, University of Massachusetts Medical School, Worcester, MA, USA.
3. Biomedical Research Institute, Department of Chemistry, New York University, New York, NY, USA.
4. Department of Chemistry, University of Alberta, Edmonton, AB, Canada.
5. Department of Medicine, The San Francisco Veterans Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, USA.