1. Department of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, IL, 61822, USA
2. School of Chemical Sciences NMR Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61822, USA
3. Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61822, USA