1. Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill School of Medicine , Chapel Hill, NC 27599 , USA
2. Department of Biochemistry and Institute for Molecular Virology, University of Wisconsin-Madison , Madison , WI 53706 , USA
3. Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park , PA 16802 , USA
4. Department of Medicinal Chemistry, University of Minnesota , Minneapolis , MN 55455 , USA
5. Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam , Amsterdam , The Netherlands
6. Junior Research Group 2, Interdisciplinary Center for Clinical Research, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Cauerstr. 3, 91058 Erlangen , Germany
7. Gilead Sciences, Inc , Foster City , CA 94404 , USA