Structural basis for DNA targeting by the Tn7 transposon
| Autor: | Alba Guarné, Yao Shen, Michael T. Petassi, Joaquin Ortega, Joseph E. Peters, Josué Gómez-Blanco |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
Transposable element
DNA Bacterial Models Molecular Dna targeting Binding Sites Escherichia coli Proteins Transposases Computational biology Basis (universal algebra) Crystallography X-Ray Substrate Specificity Transposition (music) DNA-Binding Proteins chemistry.chemical_compound chemistry Target site Structural Biology DNA Transposable Elements Escherichia coli A-DNA Protein Interaction Domains and Motifs Protein Structure Quaternary Molecular Biology Transposase DNA |
| Zdroj: | Nature Structural & Molecular Biology. 29:143-151 |
| ISSN: | 1545-9985 1545-9993 |
| Popis: | Tn7 transposable elements are unique for their highly specific, and sometimes programmable, target-site selection mechanisms and precise insertions. All the elements in the Tn7-family utilize a AAA+ adaptor (TnsC) to coordinates target-site selection with transposase activation and prevent insertions at sites already containing a Tn7 element. Due to its multiple functions, TnsC is considered the linchpin in the Tn7 element. Here we present the high-resolution cryo-EM structure of TnsC bound to DNA using a gain-of-function variant of the protein and a DNA substrate that together recapitulate the recruitment to a specific DNA target site. We find that TnsC forms an asymmetric ring on target DNA that segregates target-site selection and transposase recruitment to opposite faces of the ring. Unlike most AAA+ ATPases, TnsC uses a DNA distortion to find the target site but does not remodel DNA to activate transposition. By recognizing pre-distorted substrates, TnsC creates a built-in regulatory mechanism where ATP-hydrolysis abolishes ring formation proximal to an existing element. This work unveils how Tn7 and Tn7-like elements determine the strict spacing between the target and integration sites. |
| Databáze: | OpenAIRE |
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