1. Shanghai Institute for Advanced Immunochemical StudiesShanghaiTech University Shanghai 201210 China
2. School of Life Science and Technology ShanghaiTech University Shanghai 201210 China
3. Institute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesChinese Academy of Sciences Shanghai 200031 China
4. University of Chinese Academy of Sciences Beijing 100049 China
5. Laboratory of Molecular GeneticsHoward Hughes Medical InstituteThe Rockefeller University New York NY 10065 USA
6. Department of ChemistryScripps Research Institute La Jolla CA 92037 USA