7MCS

Cryo-electron microscopy structure of TnsC(1-503)A225V bound to DNA

Summary for 7MCS

• Entry DOI: 10.2210/pdb7mcs/pdb
• EMDB information: 23757
• Descriptor: Transposon Tn7 transposition protein TnsC, DNA (5'-D(P*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*C)-3'), DNA (5'-D(P*GP*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*CP*G)-3'), ... (5 entities in total)
• Functional Keywords: aaa+ atpase, dna binding, transposition, complex, dna binding protein, dna binding protein-dna complex, dna binding protein/dna
• Biological source: Escherichia coli; More
• Total number of polymer chains: 9
• Total formula weight: 427797.76

Authors

Shen, Y.,Ortega, J.,Guarne, A. (deposition date: 2021-04-02, release date: 2022-02-23, Last modification date: 2024-05-29)

Primary citation

Shen, Y.,Gomez-Blanco, J.,Petassi, M.T.,Peters, J.E.,Ortega, J.,Guarne, A.
Structural basis for DNA targeting by the Tn7 transposon.
Nat.Struct.Mol.Biol., 29:143-151, 2022

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+ 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.

PubMed: 35173349
DOI: 10.1038/s41594-022-00724-8

Experimental method

ELECTRON MICROSCOPY (3.56 Å)