1. Life
Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109-2216, United States
2. Program
in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109-2216, United States
3. Institute
for Neurodegenerative Diseases, Department of Pharmaceutical Chemistry, University of California—San Francisco, San Francisco, California 94143-0518, United States
4. Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States