Download MendeleyConformational toggling controls target site choice for the heteromeric transposase element Tn7.
Shi, Q., Straus, M.R., Caron, J.J., Wang, H., Chung, Y.S., Guarne, A., Peters, J.E.(2015) Nucleic Acids Res 43: 10734-10745
- PubMed: 26384427
- DOI: https://doi.org/10.1093/nar/gkv913
- Primary Citation of Related Structures:
5D16, 5D17 - PubMed Abstract:
The bacterial transposon Tn7 facilitates horizontal transfer by directing transposition into actively replicating DNA with the element-encoded protein TnsE. Structural analysis of the C-terminal domain of wild-type TnsE identified a novel protein fold including a central V-shaped loop that toggles between two distinct conformations. The structure of a robust TnsE gain-of-activity variant has this loop locked in a single conformation, suggesting that conformational flexibility regulates TnsE activity. Structure-based analysis of a series of TnsE mutants relates transposition activity to DNA binding stability. Wild-type TnsE appears to naturally form an unstable complex with a target DNA, whereas mutant combinations required for large changes in transposition frequency and targeting stabilized this interaction. Collectively, our work unveils a unique structural proofreading mechanism where toggling between two conformations regulates target commitment by limiting the stability of target DNA engagement until an appropriate insertion site is identified.
Organizational Affiliation:
Department of Microbiology, Cornell University, Ithaca, NY 14853, USA.
