4AN8

Structure of Thermus thermophilus CasA (Cse1)

4AN8 の概要

• エントリーDOI: 10.2210/pdb4an8/pdb
• 分子名称: CSE1, ACETATE ION (3 entities in total)
• 機能のキーワード: immune system, crispr, cascade, casa
• 由来する生物種: THERMUS THERMOPHILUS
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 113267.89

構造登録者

Sashital, D.G.,Wiedenheft, B.,Doudna, J.A. (登録日: 2012-03-16, 公開日: 2012-05-02, 最終更新日: 2024-11-20)

主引用文献

Sashital, D.G.,Wiedenheft, B.,Doudna, J.A.
Mechanism of Foreign DNA Selection in a Bacterial Adaptive Immune System.
Mol.Cell, 46:606-, 2012

PubMed Abstract: In bacterial and archaeal CRISPR immune pathways, DNA sequences from invading bacteriophage or plasmids are integrated into CRISPR loci within the host genome, conferring immunity against subsequent infections. The ribonucleoprotein complex Cascade utilizes RNAs generated from these loci to target complementary "nonself" DNA sequences for destruction, while avoiding binding to "self" sequences within the CRISPR locus. Here we show that CasA, the largest protein subunit of Cascade, is required for nonself target recognition and binding. Combining a 2.3 Å crystal structure of CasA with cryo-EM structures of Cascade, we have identified a loop that is required for viral defense. This loop contacts a conserved three base pair motif that is required for nonself target selection. Our data suggest a model in which the CasA loop scans DNA for this short motif prior to target destabilization and binding, maximizing the efficiency of DNA surveillance by Cascade.

PubMed: 22521690
DOI: 10.1016/J.MOLCEL.2012.03.020

実験手法

X-RAY DIFFRACTION (2.3 Å)