1. Department of Chemistry, Stanford University, Stanford, California 94305, United States
2. Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
3. State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 211198, China
4. Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211198, China
5. Department of Biology, Stanford University, Stanford, California 94305, United States
6. Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States