8DFA

type I-C Cascade bound to ssDNA target

8DFA の概要

• エントリーDOI: 10.2210/pdb8dfa/pdb
• EMDBエントリー: 27403
• 分子名称: pre-crRNA processing endonuclease, CRISPR-associated protein, TM1801 family, CRISPR-associated protein, CT1133 family, ... (6 entities in total)
• 機能のキーワード: crispr, type i-c, cascade, ssdna target, dna binding protein, dna binding protein-dna-rna complex, dna binding protein/dna/rna
• 由来する生物種: Desulfovibrio vulgaris str. Hildenborough; 詳細
• タンパク質・核酸の鎖数: 13
• 化学式量合計: 368984.84

構造登録者

O'Brien, R.E.,Bravo, J.P.K.,Ramos, D.,Hibshman, G.N.,Wright, J.T.,Taylor, D.W. (登録日: 2022-06-21, 公開日: 2023-02-22, 最終更新日: 2025-05-28)

主引用文献

O'Brien, R.E.,Bravo, J.P.K.,Ramos, D.,Hibshman, G.N.,Wright, J.T.,Taylor, D.W.
Structural snapshots of R-loop formation by a type I-C CRISPR Cascade.
Mol.Cell, 83:746-, 2023

PubMed Abstract: Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various stages of double-stranded (ds)DNA target capture, revealing mechanisms that underpin PAM recognition and Cascade allosteric activation. We uncover an interesting mechanism of non-target strand (NTS) DNA stabilization via stacking interactions with the "belly" subunits, securing the NTS in place. This "molecular seatbelt" mechanism facilitates efficient R-loop formation and prevents dsDNA reannealing. Additionally, we provide structural insights into how two anti-CRISPR (Acr) proteins utilize distinct strategies to achieve a shared mechanism of type I-C Cascade inhibition by blocking PAM scanning. These observations form a structural basis for directional R-loop formation and reveal how different Acr proteins have converged upon common molecular mechanisms to efficiently shut down CRISPR immunity.

PubMed: 36805026
DOI: 10.1016/j.molcel.2023.01.024

実験手法

ELECTRON MICROSCOPY (2.8 Å)