1 Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA.
2 Committee on Immunology, The University of Chicago, Chicago, IL, 60637, USA.
3 Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, 60637, USA.
4 Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, 60637, USA. chuanhe@uchicago.edu.
5 Committee on Immunology, The University of Chicago, Chicago, IL, 60637, USA. chuanhe@uchicago.edu.
6 Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, 60637, USA. chuanhe@uchicago.edu.