EMD-29039

Single-particle
3.6 Å
EMD-29039 Deposition: 07/12/2022
Map released: 09/08/2023
Last modified: 31/01/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-29039

Cryo-EM structure of Cascade-DNA-TniQ-TnsC complex (composite) in type I-B CAST system

EMD-29039

Single-particle
3.6 Å
EMD-29039 Deposition: 07/12/2022
Map released: 09/08/2023
Last modified: 31/01/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Nostoc sp. 'Peltigera membranacea cyanobiont' 210A, synthetic construct, Peltigera membranacea
Sample: Structure of Cascade-DNA-TniQ-TnsC complex (composite) in type I-B CAST system
Fitted models: 8ff4 (Avg. Q-score: 0.417)

Deposition Authors: Chang L , Wang S
Molecular mechanism for Tn7-like transposon recruitment by a type I-B CRISPR effector.
Wang S , Gabel C , Siddique R, Klose T, Chang L
(2023) Cell , 186 , 4204 - 4215.e19
PUBMED: 37557170
DOI: doi:10.1016/j.cell.2023.07.010
ISSN: 1097-4172
Abstract:
Tn7-like transposons have co-opted CRISPR-Cas systems to facilitate the movement of their own DNA. These CRISPR-associated transposons (CASTs) are promising tools for programmable gene knockin. A key feature of CASTs is their ability to recruit Tn7-like transposons to nuclease-deficient CRISPR effectors. However, how Tn7-like transposons are recruited by diverse CRISPR effectors remains poorly understood. Here, we present the cryo-EM structure of a recruitment complex comprising the Cascade complex, TniQ, TnsC, and the target DNA in the type I-B CAST from Peltigera membranacea cyanobiont 210A. Target DNA recognition by Cascade induces conformational changes in Cas6 and primes TniQ recruitment through its C-terminal domain. The N-terminal domain of TniQ is bound to the seam region of the TnsC spiral heptamer. Our findings provide insights into the diverse mechanisms for the recruitment of Tn7-like transposons to CRISPR effectors and will aid in the development of CASTs as gene knockin tools.