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-Structure paper
Title | Assembly of the Tn7 targeting complex by a regulated stepwise process. |
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Journal, issue, pages | Mol Cell, Vol. 84, Issue 12, Page 2368-22381.e6, Year 2024 |
Publish date | Jun 20, 2024 |
Authors | Yao Shen / Shreya S Krishnan / Michael T Petassi / Mark A Hancock / Joseph E Peters / Alba Guarné / |
PubMed Abstract | The Tn7 family of transposons is notable for its highly regulated integration mechanisms, including programmable RNA-guided transposition. The targeting pathways rely on dedicated target selection ...The Tn7 family of transposons is notable for its highly regulated integration mechanisms, including programmable RNA-guided transposition. The targeting pathways rely on dedicated target selection proteins from the TniQ family and the AAA+ adaptor TnsC to recruit and activate the transposase at specific target sites. Here, we report the cryoelectron microscopy (cryo-EM) structures of TnsC bound to the TniQ domain of TnsD from prototypical Tn7 and unveil key regulatory steps stemming from unique behaviors of ATP- versus ADP-bound TnsC. We show that TnsD recruits ADP-bound dimers of TnsC and acts as an exchange factor to release one protomer with exchange to ATP. This loading process explains how TnsC assembles a heptameric ring unidirectionally from the target site. This unique loading process results in functionally distinct TnsC protomers within the ring, providing a checkpoint for target immunity and explaining how insertions at programmed sites precisely occur in a specific orientation across Tn7 elements. |
External links | Mol Cell / PubMed:38834067 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.32 - 3.88 Å |
Structure data | EMDB-40218, PDB-8glu: EMDB-40221, PDB-8glw: EMDB-40222, PDB-8glx: EMDB-43138, PDB-8vcj: EMDB-43140, PDB-8vct: |
Chemicals | ChemComp-ATP: ChemComp-MG: ChemComp-ZN: ChemComp-ADP: ChemComp-AGS: |
Source |
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Keywords | DNA BINDING PROTEIN / Transposon / AAA+ ATPase / Oligomer / Complex / DNA BINDING PROTEIN/DNA / DNA BINDING PROTEIN-DNA complex / DNA-binding protein DNA complex |