1. Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
2. Department of Microbiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
3. Integrative Program for Biological & Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
4. Department of Biochemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA