1. Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
2. Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States
3. Howard Hughes Medical Institute, University of Illinois at Urbana–Champaign, Urbana, Illinois 61801, United States