1. Department of Bioengineering, University of Illinois at Urbana-Champaign , Urbana, IL 61801, USA
2. Biotechnology and Bioengineering Department, Sandia National Laboratories , Livermore, CA 94550, USA
3. Department of Microbiology, University of Illinois at Urbana-Champaign , Urbana, IL 61801, USA
4. Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, IL 61801, USA