1. School of Life Sciences; Tsinghua-Peking Joint Center for Life Sciences; Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
2. Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
3. Spark Therapeutics, 3737 Market Street, Philadelphia, PA, 19104, USA
4. Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA