1. Masonic
Cancer Center and Departments of Chemistry and Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
2. Department
of Chemistry, University of California, Davis, California 95616, United States
3. Division
of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
4. Department
of Pharmacology, University of Minnesota, Minneapolis, Minnesota 55455, United States