8WM4

Cryo-EM structure of DiCas7-11 in complex with crRNA

Summary for 8WM4

• Entry DOI: 10.2210/pdb8wm4/pdb
• EMDB information: 37640
• Descriptor: CRISPR-associated RAMP family protein, crRNA (38-MER), ZINC ION (3 entities in total)
• Functional Keywords: crispr-cas, gene editing, tpr-chat, immune system
• Biological source: Desulfonema ishimotonii; More
• Total number of polymer chains: 2
• Total formula weight: 196328.77

Authors

Ma, H.Y.,Tang, X.D. (deposition date: 2023-10-02, release date: 2024-05-29, Last modification date: 2025-06-18)

Primary citation

Hong, T.,Luo, Q.,Ma, H.,Wang, X.,Li, X.,Shen, C.,Pang, J.,Wang, Y.,Chen, Y.,Zhang, C.,Su, Z.,Dong, H.,Tang, X.
Structural basis of negative regulation of CRISPR-Cas7-11 by TPR-CHAT.
Signal Transduct Target Ther, 9:111-111, 2024

PubMed Abstract: CRISPR‒Cas7-11 is a Type III-E CRISPR-associated nuclease that functions as a potent RNA editing tool. Tetratrico-peptide repeat fused with Cas/HEF1-associated signal transducer (TPR-CHAT) acts as a regulatory protein that interacts with CRISPR RNA (crRNA)-bound Cas7-11 to form a CRISPR-guided caspase complex (Craspase). However, the precise modulation of Cas7-11's nuclease activity by TPR-CHAT to enhance its utility requires further study. Here, we report cryo-electron microscopy (cryo-EM) structures of Desulfonema ishimotonii (Di) Cas7-11-crRNA, complexed with or without the full length or the N-terminus of TPR-CHAT. These structures unveil the molecular features of the Craspase complex. Structural analysis, combined with in vitro nuclease assay and electrophoretic mobility shift assay, reveals that DiTPR-CHAT negatively regulates the activity of DiCas7-11 by preventing target RNA from binding through the N-terminal 65 amino acids of DiTPR-CHAT (DiTPR-CHAT). Our work demonstrates that DiTPR-CHAT can function as a small unit of DiCas7-11 regulator, potentially enabling safe applications to prevent overcutting and off-target effects of the CRISPR‒Cas7-11 system.

PubMed: 38735995
DOI: 10.1038/s41392-024-01821-4

Experimental method

ELECTRON MICROSCOPY (2.93 Å)