Kevin D Corbett1,2, Mark A Herzik3. 1. Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA. kcorbett@ucsd.edu. 2. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. kcorbett@ucsd.edu. 3. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA. mherzik@ucsd.edu.