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Title | Structural basis for DNA targeting by the Tn7 transposon. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 29, Issue 2, Page 143-151, Year 2022 |
Publish date | Feb 16, 2022 |
Authors | Yao Shen / Josue Gomez-Blanco / Michael T Petassi / Joseph E Peters / Joaquin Ortega / Alba Guarné / |
PubMed Abstract | 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 an AAA+ ...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 an AAA+ adaptor (TnsC) to coordinate target-site selection with transpososome assembly and to prevent insertions at sites already containing a Tn7 element. Owing 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. TnsC forms an asymmetric ring on target DNA that segregates target-site selection and interaction with the paired-end complex 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. |
External links | Nat Struct Mol Biol / PubMed:35173349 |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 3.2 - 3.56 Å |
Structure data | EMDB-23757, PDB-7mcs: PDB-7mbw: |
Chemicals | ChemComp-ADP: ChemComp-MG: ChemComp-HOH: ChemComp-ANP: |
Source |
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Keywords | DNA BINDING PROTEIN / AAA+ ATPase / Transposition / DNA binding / DNA BINDING PROTEIN/DNA / Complex / DNA BINDING PROTEIN-DNA complex |