Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA. emmitt.jolly@itsa.ucsf.edu|Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA. emmitt.jolly@itsa.ucsf.edu|Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA. emmitt.jolly@itsa.ucsf.edu|Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA. emmitt.jolly@itsa.ucsf.edu