EMD-33439

Single-particle
3.08 Å
EMD-33439 Deposition: 16/05/2022
Map released: 09/11/2022
Last modified: 03/07/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-33439

Structure of Craspase-NTR

EMD-33439

Single-particle
3.08 Å
EMD-33439 Deposition: 16/05/2022
Map released: 09/11/2022
Last modified: 03/07/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Candidatus Scalindua brodae
Sample: Craspase-NTR complex
Fitted models: 7xt4 (Avg. Q-score: 0.536)

Deposition Authors: Feng Y , Zhang L
Target RNA activates the protease activity of Craspase to confer antiviral defense.
Liu X, Zhang L, Wang H, Xiu Y, Huang L, Gao Z, Li N, Li F, Xiong W , Gao T, Zhang Y, Yang M , Feng Y
(2022) Mol Cell , 82 , 4503 - 4518.e8
PUBMED: 36306795
DOI: doi:10.1016/j.molcel.2022.10.007
ISSN: 1097-2765
ASTM: MOCEFL
Abstract:
In the type III-E CRISPR-Cas system, a Cas effector (gRAMP) is associated with a TPR-CHAT to form Craspase (CRISPR-guided caspase). However, both the structural features of gRAMP and the immunity mechanism remain unknown for this system. Here, we report structures of gRAMP-crRNA and gRAMP:cRNA:target RNA as well as structures of Craspase and Craspase complexed with cognate target RNA (CTR) or non-cognate target RNA (NTR). Importantly, the 3' anti-tag region of NTR and CTR binds at two distinct channels in Craspase, and CTR with a non-complementary 3' anti-tag induces a marked conformational change of the TPR-CHAT, which allosterically activates its protease activity to cleave an ancillary protein Csx30. This cleavage then triggers an abortive infection as the antiviral strategy of the type III-E system. Together, our study provides crucial insights into both the catalytic mechanism of the gRAMP and the immunity mechanism of the type III-E system.