Structural highlights
FunctionTNSE_ECOLX TnsABC + TnsD promote high-frequency insertion of Tn7 into a specific target site known as att-Tn7 whereas TnsABC + TnsE promote low-frequency insertion into many different sites. Publication Abstract from PubMedThe 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. Conformational toggling controls target site choice for the heteromeric transposase element Tn7.,Shi Q, Straus MR, Caron JJ, Wang H, Chung YS, Guarne A, Peters JE Nucleic Acids Res. 2015 Sep 17. pii: gkv913. PMID:26384427[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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