8GLX

CryoEM structure of the TnsC(1-503)-TnsD(1-318)-DNA complex in a 6:2:1 stoichiometry from E. coli Tn7

Summary for 8GLX

• Entry DOI: 10.2210/pdb8glx/pdb
• Related: 8GLU 8GLW
• EMDB information: 40218 40221 40222
• Descriptor: Transposon Tn7 transposition protein TnsC, Transposon Tn7 transposition protein TnsD, DNA (50-MER), ... (8 entities in total)
• Functional Keywords: transposon, aaa+ atpase, oligomer, complex, dna binding protein, dna binding protein-dna complex, dna binding protein/dna
• Biological source: Escherichia coli; More
• Total number of polymer chains: 10
• Total formula weight: 462991.16

Authors

Shen, Y.,Guarne, A. (deposition date: 2023-03-23, release date: 2024-07-31)

Primary citation

Shen, Y.,Krishnan, S.S.,Petassi, M.T.,Hancock, M.A.,Peters, J.E.,Guarne, A.
Assembly of the Tn7 targeting complex by a regulated stepwise process.
Mol.Cell, 84:2368-2381.e6, 2024

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 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.

PubMed: 38834067
DOI: 10.1016/j.molcel.2024.05.012

Experimental method

ELECTRON MICROSCOPY (3.88 Å)