About the Authors

Douglas L Theobald

To whom correspondence should be addressed. E-mail: dtheobald@brandeis.edu

Affiliation Department of Biochemistry, Brandeis University, Waltham, Massachusetts, United States of America

Deborah S Wuttke

Affiliation Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

DLT and DWS conceived and designed the experiments, analyzed the data, and wrote the paper. DLT performed the experiments and contributed reagents/materials/analysis tools.