1. Department
of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-6600, United States
2. Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240-7917, United States
3. Chemical
and Physical Biology Program, Vanderbilt University, Nashville, Tennessee 37232-0301, United States
4. Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
5. Department
of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee 37232-2561, United States
6. Neuroscience
Program, Vanderbilt University, Nashville, Tennessee 37235, United States
7. Department
of Biochemistry, University of Washington, Seattle, Washington 98195, United States