1. Department of Biochemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
2. Department of Bacteriology, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
3. Microbiology Doctoral Training Program, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
4. Department of Chemical & Biological Engineering, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States