1. Department of Biochemistry, University of Washington, Seattle, WA, USA.
2. Institute for Protein Design, University of Washington, Seattle, WA, USA.
3. Molecular Engineering Graduate Program, University of Washington, Seattle, WA, USA.
4. Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
5. Department of Physical Chemistry and Soft Matter, Wageningen University and Research, Wageningen, Netherlands.
6. Berkeley Center for Structural Biology, Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley Laboratory, Berkeley, CA, USA.