About the Authors
Department of Pharmaceutical Chemistry, University of California, San Francisco, California, United States of America
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: ZL ML SM PE. Performed the experiments: ZL ML SM. Analyzed the data: ZL ML PE CW. Wrote the paper: ZL PE CW.