1. Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
2. State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
3. Department of Cell and Developmental Biology, Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
4. Roy J. Carver Biotechnology Center, Protein Sciences Facility, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
5. Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States