About the Authors

Yakov Korkhin

Affiliations Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America , Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, United States of America , Harvard Medical School, Boston, Massachusetts, United States of America , Howard Hughes Medical Institute, Harvard University, Boston, Massachusetts, United States of America

Ulug M Unligil

Affiliations Harvard Medical School, Boston, Massachusetts, United States of America , Howard Hughes Medical Institute, Harvard University, Boston, Massachusetts, United States of America

Otis Littlefield

Affiliations Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America , Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, United States of America

Pamlea J Nelson

Affiliations Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America , Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, United States of America , Harvard Medical School, Boston, Massachusetts, United States of America , Howard Hughes Medical Institute, Harvard University, Boston, Massachusetts, United States of America

David I Stuart

Affiliation Division of Structural Biology and the Oxford Protein Production Facility, The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom

Paul B Sigler

† Deceased.

Affiliations Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America , Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, United States of America

Stephen D Bell

Affiliation Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom

Nicola G. A Abrescia

To whom correspondence should be addressed. E-mail: nabrescia@cicbiogune.es

Affiliations Division of Structural Biology and the Oxford Protein Production Facility, The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom , Structural Biology Unit, CIC bioGUNE, Derio, Spain

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

YK, PBS, SDB, and NGAA conceived and designed the experiments. YK, UMU, OL, PJN, SDB, and NGAA performed the experiments. YK, PBS, DIS, SDB, and NGAA analyzed the data. DIS, SDB, and NGAA wrote the paper.