1. Department of Immunology and Microbiology, Scripps Research, La Jolla, California 92037, United States
2. Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
3. Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
4. Department of Chemistry, Scripps Research, La Jolla, California 92037, United States