1. Fundamental & Computational Sciences Directorate Pacific Northwest National Laboratory Richland WA 99352 USA
2. Department of Microbiology University of Minnesota St. Paul MN 55108 USA
3. Center for Molecular and Structural Biochemistry School of Biological Sciences and School of Chemistry University of East Anglia Norwich NR4 7TJ UK
4. The Gene and Linda Voiland School of Chemical Engineering and Bioengineering Washington State University Pullman WA 99164 USA