5U07

CRISPR RNA-guided surveillance complex

5U07 の概要

• エントリーDOI: 10.2210/pdb5u07/pdb
• 関連するPDBエントリー: 5U0A
• EMDBエントリー: 8477 8478
• 分子名称: CRISPR-associated protein, Cse3 family, Cse2, CRISPR-associated protein, Cse1 family, ... (8 entities in total)
• 機能のキーワード: crispr-cas, cascade, immune system
• 由来する生物種: Thermobifida fusca YX; 詳細
• タンパク質・核酸の鎖数: 14
• 化学式量合計: 447350.48

構造登録者

Xiao, Y.,Luo, M.,Hayes, R.P.,Kim, J.,Ng, S.,Ding, F.,Liao, M.,Ke, A. (登録日: 2016-11-23, 公開日: 2017-08-09, 最終更新日: 2024-03-13)

主引用文献

Xiao, Y.,Luo, M.,Hayes, R.P.,Kim, J.,Ng, S.,Ding, F.,Liao, M.,Ke, A.
Structure Basis for Directional R-loop Formation and Substrate Handover Mechanisms in Type I CRISPR-Cas System.
Cell, 170:48-60.e11, 2017

PubMed Abstract: Type I CRISPR systems feature a sequential dsDNA target searching and degradation process, by crRNA-displaying Cascade and nuclease-helicase fusion enzyme Cas3, respectively. Here we present two cryo-EM snapshots of the Thermobifida fusca type I-E Cascade: (1) unwinding 11 bp of dsDNA at the seed-sequence region to scout for sequence complementarity, and (2) further unwinding of the entire protospacer to form a full R-loop. These structures provide the much-needed temporal and spatial resolution to resolve key mechanistic steps leading to Cas3 recruitment. In the early steps, PAM recognition causes severe DNA bending, leading to spontaneous DNA unwinding to form a seed-bubble. The full R-loop formation triggers conformational changes in Cascade, licensing Cas3 to bind. The same process also generates a bulge in the non-target DNA strand, enabling its handover to Cas3 for cleavage. The combination of both negative and positive checkpoints ensures stringent yet efficient target degradation in type I CRISPR-Cas systems.

PubMed: 28666122
DOI: 10.1016/j.cell.2017.06.012

実験手法

ELECTRON MICROSCOPY (3.8 Å)