6MUS

Cryo-EM structure of larger Csm-crRNA-target RNA ternary complex in type III-A CRISPR-Cas system

6MUS の概要

• エントリーDOI: 10.2210/pdb6mus/pdb
• 関連するPDBエントリー: 6MUA 6MUR
• EMDBエントリー: 9253 9254
• 分子名称: Uncharacterized protein Csm1, Uncharacterized protein Csm2, Uncharacterized protein Csm3, ... (8 entities in total)
• 機能のキーワード: cryo-em structure, larger csm-crrna-target rna ternary complex, type iii crispr-cas systerm, rna binding protein-rna complex, rna binding protein/rna
• 由来する生物種: Thermococcus onnurineus; 詳細
• タンパク質・核酸の鎖数: 10
• 化学式量合計: 334309.95

構造登録者

Jia, N.,Wang, C.,Eng, E.T. (登録日: 2018-10-23, 公開日: 2018-12-12, 最終更新日: 2024-11-13)

主引用文献

Jia, N.,Mo, C.Y.,Wang, C.,Eng, E.T.,Marraffini, L.A.,Patel, D.J.
Type III-A CRISPR-Cas Csm Complexes: Assembly, Periodic RNA Cleavage, DNase Activity Regulation, and Autoimmunity.
Mol. Cell, 73:264-, 2019

PubMed Abstract: Type ΙΙΙ CRISPR-Cas systems provide robust immunity against foreign RNA and DNA by sequence-specific RNase and target RNA-activated sequence-nonspecific DNase and RNase activities. We report on cryo-EM structures of Thermococcus onnurineus Csm binary, Csm-target RNA and Csm-target RNA ternary complexes in the 3.1 Å range. The topological features of the crRNA 5'-repeat tag explains the 5'-ruler mechanism for defining target cleavage sites, with accessibility of positions -2 to -5 within the 5'-repeat serving as sensors for avoidance of autoimmunity. The Csm3 thumb elements introduce periodic kinks in the crRNA-target RNA duplex, facilitating cleavage of the target RNA with 6-nt periodicity. Key Glu residues within a Csm1 loop segment of Csm adopt a proposed autoinhibitory conformation suggestive of DNase activity regulation. These structural findings, complemented by mutational studies of key intermolecular contacts, provide insights into Csm complex assembly, mechanisms underlying RNA targeting and site-specific periodic cleavage, regulation of DNase cleavage activity, and autoimmunity suppression.

PubMed: 30503773
DOI: 10.1016/j.molcel.2018.11.007

実験手法

ELECTRON MICROSCOPY (3.6 Å)