7Y83

CryoEM structure of type III-E CRISPR Craspase gRAMP-crRNA in complex with TPR-CHAT protease bound to non-self RNA target

Summary for 7Y83

• Entry DOI: 10.2210/pdb7y83/pdb
• EMDB information: 33679
• Descriptor: RAMP superfamily protein, crRNA, non-self RNA, ... (6 entities in total)
• Functional Keywords: nuclease, structural protein-rna complex, structural protein/rna
• Biological source: Candidatus Scalindua brodae; More
• Total number of polymer chains: 4
• Total formula weight: 337991.66

Authors

Zhang, J.T.,Cui, N.,Huang, H.D.,Jia, N. (deposition date: 2022-06-22, release date: 2022-12-14, Last modification date: 2024-05-08)

Primary citation

Cui, N.,Zhang, J.T.,Li, Z.,Liu, X.Y.,Wang, C.,Huang, H.,Jia, N.
Structural basis for the non-self RNA-activated protease activity of the type III-E CRISPR nuclease-protease Craspase.
Nat Commun, 13:7549-7549, 2022

PubMed Abstract: The RNA-targeting type III-E CRISPR-gRAMP effector interacts with a caspase-like protease TPR-CHAT to form the CRISPR-guided caspase complex (Craspase), but their functional mechanism is unknown. Here, we report cryo-EM structures of the type III-E gRAMP and gRAMP-TPR-CHAT complexes, before and after either self or non-self RNA target binding, and elucidate the mechanisms underlying RNA-targeting and non-self RNA-induced protease activation. The associated TPR-CHAT adopted a distinct conformation upon self versus non-self RNA target binding, with nucleotides at positions -1 and -2 of the CRISPR-derived RNA (crRNA) serving as a sensor. Only binding of the non-self RNA target activated the TPR-CHAT protease, leading to cleavage of Csx30 protein. Furthermore, TPR-CHAT structurally resembled eukaryotic separase, but with a distinct mechanism for protease regulation. Our findings should facilitate the development of gRAMP-based RNA manipulation tools, and advance our understanding of the virus-host discrimination process governed by a nuclease-protease Craspase during type III-E CRISPR-Cas immunity.

PubMed: 36477448
DOI: 10.1038/s41467-022-35275-5

Experimental method

ELECTRON MICROSCOPY (2.93 Å)