1. Department
of Chemistry and Howard Hughes Medical Institute, University of Illinois at Urbana−Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
2. Institute
for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, United States
3. Department
of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
4. Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States