1. Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
2. Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
3. Department of Pharmacology & Pharmaceutical Sciences, School of Medicine, Tsinghua University, Beijing 100084, P.R. China.
4. Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
5. Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, P.R. China.
6. Collaborative Innovation Center for Biotherapy, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, P.R. China.
7. Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.