1. Department of Biochemistry, University of Wisconsin-Madison , Madison, WI , USA
2. Department of Mechanical Engineering, University of Wisconsin-Madison , Madison, WI , USA
3. Biophysics Graduate Program, University of Wisconsin-Madison , Madison, WI , USA
4. Cryo-Electron Microscopy Research Center, University of Wisconsin , Madison, WI , USA
5. Mortgridge Institute for Research, University of Wisconsin-Madison , Madison, WI , USA