9IRF

Cryo-EM Structure of csy1-4 with crRNA

9IRF の概要

• エントリーDOI: 10.2210/pdb9irf/pdb
• EMDBエントリー: 60812
• 分子名称: CRISPR-associated protein Csy2, CRISPR-associated endonuclease Cas6f/Csy4, CRISPR-associated protein Csy3, ... (5 entities in total)
• 機能のキーワード: crrna, cas6f, cas7f, cas5f, cas8f, rna binding protein/rna, rna binding protein-rna complex
• 由来する生物種: Pectobacterium atrosepticum SCRI1043; 詳細
• タンパク質・核酸の鎖数: 10
• 化学式量合計: 355596.19

構造登録者

Gao, X.,Cui, S.,Zhu, H.,Zhu, K.,Shang, K. (登録日: 2024-07-15, 公開日: 2026-01-14)

主引用文献

Gao, X.,Zhu, K.,Zhang, W.,Wang, L.,Wang, L.,Hua, L.,Niu, T.,Qin, B.,Yu, X.,Zhu, H.,Cui, S.
RNA anti-CRISPRs deplete Cas proteins to inhibit the CRISPR-Cas system.
Mol.Cell, 2025

PubMed Abstract: RNA-based anti-CRISPRs (Racrs) interfere with the type I-F CRISPR-Cas system by mimicking the repeats found in CRISPR arrays. Here, we determined the cryo-electron microscopy (cryo-EM) structures of the type I-F crRNA-guided surveillance complex (Csy complex) from Pectobacterium atrosepticum and three RacrIF1-induced aberrant subcomplexes. Additionally, we observed that Cas7f proteins could bind to non-specific nucleic acids, forming right-handed superhelical filaments composed of different Cas7 copies. Mechanistically, RacrIF1 lacks the specific S-conformation observed in the corresponding position of the 5' handle in canonical CRISPR complexes, and it instead adopts a periodic "5 + 1" pattern. This conformation creates severe steric hindrance for Cas5f-Cas8f heterodimer and undermines their binding. Furthermore, Cas7f nonspecifically binds nucleic acids and can form infinite superhelical filaments along Racrs molecules. This oligomerization sequesters Cas6f and Cas7f from binding, therefore blocking the formation of functional CRISPR-Cas effector complexes and ultimately blocking antiviral immunity. Our study provides a structural basis underlying Racrs-mediated CRISPRs inhibition.

PubMed: 41475348
DOI: 10.1016/j.molcel.2025.12.005

実験手法

ELECTRON MICROSCOPY (2.8 Å)