Pujuan Deng1,2, Jun-Jie Gogo Liu3,4. 1. Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China. 2. Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China. 3. Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China. junjiegogoliu@tsinghua.edu.cn. 4. Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China. junjiegogoliu@tsinghua.edu.cn.