7U5D

I-F3b Cascade-TniQ full R-loop complex

Summary for 7U5D

• Entry DOI: 10.2210/pdb7u5d/pdb
• EMDB information: 26348
• Descriptor: crRNA, Target strand DNA, Non-target strand DNA, ... (7 entities in total)
• Functional Keywords: crispr-cas, transposon, cast, cascade, i-f, i-f3, dna binding protein, dna binding protein-dna-rna complex, dna binding protein/dna/rna
• Biological source: Aeromonas salmonicida; More
• Total number of polymer chains: 13
• Total formula weight: 520484.51

Authors

Park, J.U.,Mehrotra, E.,Kellogg, E.H. (deposition date: 2022-03-02, release date: 2023-06-21, Last modification date: 2024-06-12)

Primary citation

Park, J.U.,Petassi, M.T.,Hsieh, S.C.,Mehrotra, E.,Schuler, G.,Budhathoki, J.,Truong, V.H.,Thyme, S.B.,Ke, A.,Kellogg, E.H.,Peters, J.E.
Multiple adaptations underly co-option of a CRISPR surveillance complex for RNA-guided DNA transposition.
Mol.Cell, 83:1827-1838.e6, 2023

PubMed Abstract: CRISPR-associated transposons (CASTs) are natural RNA-directed transposition systems. We demonstrate that transposon protein TniQ plays a central role in promoting R-loop formation by RNA-guided DNA-targeting modules. TniQ residues, proximal to CRISPR RNA (crRNA), are required for recognizing different crRNA categories, revealing an unappreciated role of TniQ to direct transposition into different classes of crRNA targets. To investigate adaptations allowing CAST elements to utilize attachment sites inaccessible to CRISPR-Cas surveillance complexes, we compared and contrasted PAM sequence requirements in both I-F3b CAST and I-F1 CRISPR-Cas systems. We identify specific amino acids that enable a wider range of PAM sequences to be accommodated in I-F3b CAST elements compared with I-F1 CRISPR-Cas, enabling CAST elements to access attachment sites as sequences drift and evade host surveillance. Together, this evidence points to the central role of TniQ in facilitating the acquisition of CRISPR effector complexes for RNA-guided DNA transposition.

PubMed: 37267904
DOI: 10.1016/j.molcel.2023.05.005

Experimental method

ELECTRON MICROSCOPY (3.52 Å)