1. Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
2. Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, and North Carolina State University,
Raleigh, North Carolina 27695, United States
3. Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
4. Division of Chemical Biology and Medicinal Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States