1. Department of Chemistry, University of Wisconsin-Madison College of Letters and Sciences, Madison, Wisconsin 53706, United States
2. McArdle Laboratory for Cancer Research, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin 53705, United States
3. Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
4. Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States