1. Chemistry Department, Duke University, 124 Science Drive, Durham, NC 27705, USA.
2. Department of Chemistry, Case Western Reserve University, Cleveland, OH 441106, USA.
3. Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
4. Department of Internal Medicine and Department of Microbiology and Immunology, University of Michigan, 1150 W Medical Center Dr., Ann Arbor, MI 48109, USA.
5. Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
6. MRC-University of Glasgow Centre for Virus Research, 464 Bearsden Rd., Bearsden, Glasgow G61 1QH, UK.
7. Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA.