1. Biophysics Graduate Group, University of California, Davis 95616, California, United States
2. Genome Center, University of California, Davis 95616, California, United States
3. Microbiology Graduate Group, University of California, Davis 95616, California, United States
4. Department of Biochemistry & Molecular Medicine, University of California, Davis 95616, California, United States
5. Department of Chemistry, University of California, Davis 95616, California, United States