1. Department of Chemistry and BiochemistryThe Ohio State University Columbus OH 43210 USA
2. Department of Chemistry and Biochemistry and Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of California San Diego CA 92093 USA
3. Department of Pediatrics, Division of Pediatric Infectious DiseasesWashington University School of Medicine St. Louis MO 63110 USA
4. Department of Microbiology and The Center for RNA BiologyThe Ohio State University Columbus OH 43210 USA
5. Department of Molecular MicrobiologyWashington University School of Medicine St. Louis MO 63110 USA