1. Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
2. Institute for Protein Design, University of Washington, Seattle, Washington 98195, United States
3. Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
4. Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, United States
5. Physical Sciences Division, Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States