1. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
2. Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
3. Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
4. Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016
5. Department of Biology, Faculty of Science, RNA Group, Université de Sherbrooke, Sherbrooke, J1K 2R1, QC, Canada