About the Authors
Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
European Molecular Biology Laboratory, Heidelberg, Germany
The authors have declared that no competing interests exist.
HS, BPN, and JHM conceived and designed the experiments. HS and BPN performed the experiments. HS and JHM analyzed the data. HS, BPN, and JHM contributed reagents/materials/analysis tools. HS, LMS, and JHM wrote the paper.