1. Department of Cellular and Molecular Pharmacology, University of California , San Francisco , CA 94158, USA
2. Quantitative Biosciences Institute (QBI), University of California , San Francisco , CA 94158, USA
3. Department of Microbiology, Immunology, and Molecular Genetics, University of California , Los Angeles , CA 90024, USA
4. Quantitative and Computational Biosciences Institute (QCBio), University of California , Los Angeles , CA 90024, USA
5. Department of Biochemistry and Structural Biology, University of Texas Health Science Center , San Antonio , TX 78229, USA