8Q3Y

Crystal structure of apo Can2 from Thermoanaerobacter brockii

8Q3Y の概要

• エントリーDOI: 10.2210/pdb8q3y/pdb
• 分子名称: DUF1887 family protein (2 entities in total)
• 機能のキーワード: can2, carf, crispr-cas, dna binding protein
• 由来する生物種: Thermoanaerobacter brockii subsp. finnii Ako-1
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 102800.95

構造登録者

Jungfer, K.,Sigg, A.,Jinek, M. (登録日: 2023-08-04, 公開日: 2023-11-22, 最終更新日: 2024-01-24)

主引用文献

Jungfer, K.,Sigg, A.,Jinek, M.
Substrate selectivity and catalytic activation of the type III CRISPR ancillary nuclease Can2.
Nucleic Acids Res., 52:462-473, 2024

PubMed Abstract: Type III CRISPR-Cas systems provide adaptive immunity against foreign mobile genetic elements through RNA-guided interference. Sequence-specific recognition of RNA targets by the type III effector complex triggers the generation of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins, thus reinforcing the host immune response. The ancillary nuclease Can2 is activated by cyclic tetra-AMP (cA4); however, the mechanisms underlying cA4-mediated activation and substrate selectivity remain elusive. Here we report crystal structures of Thermoanaerobacter brockii Can2 (TbrCan2) in substrate- and product-bound complexes. We show that TbrCan2 is a single strand-selective DNase and RNase that binds substrates via a conserved SxTTS active site motif, and reveal molecular interactions underpinning its sequence preference for CA dinucleotides. Furthermore, we identify a molecular interaction relay linking the cA4 binding site and the nuclease catalytic site to enable divalent metal cation coordination and catalytic activation. These findings provide key insights into the molecular mechanisms of Can2 nucleases in type III CRISPR-Cas immunity and may guide their technological development for nucleic acid detection applications.

PubMed: 38033326
DOI: 10.1093/nar/gkad1102

実験手法

X-RAY DIFFRACTION (2.52 Å)