1. Center for Biophysics and Quantitative Biology, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
2. Department of Chemistry, University of Illinois at Urbana─Champaign, Urbana, Illinois 61801, United States
3. Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana─Champaign, 1206 W. Gregory Dr, Urbana, Illinois 61801, United States