CRISPR-associated endonuclease / DNA BINDING PROTEIN / DNA BINDING PROTEIN-DNA-RNA complex
機能・相同性
機能・相同性情報
maintenance of CRISPR repeat elements / 3'-5' exonuclease activity / DNA endonuclease activity / defense response to virus / 加水分解酵素; エステル加水分解酵素 / DNA binding / RNA binding / metal ion binding 類似検索 - 分子機能
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R35GM138348
米国
Welch Foundation
F-1938-20200401
米国
American Cancer Society
RSG-21-050-01-DMC
米国
引用
ジャーナル: Nat Commun / 年: 2025 タイトル: Visualization of a multi-turnover Cas9 after product release. 著者: Kaitlyn A Kiernan / David W Taylor / 要旨: While the most widely used CRISPR-Cas enzyme is the Cas9 endonuclease from Streptococcus pyogenes (Cas9), it exhibits single-turnover enzyme kinetics which leads to long residence times on product ...While the most widely used CRISPR-Cas enzyme is the Cas9 endonuclease from Streptococcus pyogenes (Cas9), it exhibits single-turnover enzyme kinetics which leads to long residence times on product DNA. This blocks access to DNA repair machinery and acts as a major bottleneck during CRISPR-Cas9 gene editing. Cas9 can eventually be removed from the product by extrinsic factors, such as translocating polymerases, but the mechanisms contributing to Cas9 dissociation following cleavage remain poorly understood. Here, we employ truncated guide RNAs as a strategy to weaken PAM-distal nucleic acid interactions and promote faster enzyme turnover. Using kinetics-guided cryo-EM, we examine the conformational landscape of a multi-turnover Cas9, including the first detailed snapshots of Cas9 dissociating from product DNA. We discovered that while the PAM-distal product dissociates from Cas9 following cleavage, tight binding of the PAM-proximal product directly inhibits re-binding of new targets. Our work provides direct evidence as to why Cas9 acts as a single-turnover enzyme and will guide future Cas9 engineering efforts.