About the Authors

Elizabeth R Sprague

Affiliation Division of Biology, California Institute of Technology, Pasadena, California, United States of America

Chu Wang

Affiliation Department of Biochemistry, University of Washington, Seattle, Washington, United States of America

David Baker

Affiliations Department of Biochemistry, University of Washington, Seattle, Washington, United States of America , Howard Hughes Medical Institute, University of Washington, Seattle, Washington, United States of America

Pamela J Bjorkman

To whom correspondence should be addressed. E-mail: bjorkman@caltech.edu

Affiliations Division of Biology, California Institute of Technology, Pasadena, California, United States of America , Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

ERS and PJB conceived and designed the experiments. ERS and CW performed the experiments. CW and DB contributed reagents/materials/analysis tools. ERS, CW, DB, and PJB analyzed the data and wrote the paper.