1. Department
of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
2. Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
3. Department
of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37235, United States
4. Department
of Chemistry, Grand Valley State University, Allendale, Michigan 49401, United States
5. Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37235, United States