1. Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801, United States
2. Drury University, Springfield, Missouri 65802, United States
3. Department of Biological Sciences, Salisbury University, Salisbury, Maryland 21801, United States
4. Departments of Biochemistry and Chemistry, University of Illinois, Urbana, Illinois 61801, United States