7XT4

Structure of Craspase-NTR

Summary for 7XT4

• Entry DOI: 10.2210/pdb7xt4/pdb
• EMDB information: 33439
• Descriptor: CHAT domain protein, RNA (5'-R(P*GP*GP*GP*GP*CP*AP*GP*AP*AP*AP*AP*UP*UP*GP*GP*GP*UP*AP*CP*CP*G)-3'), RAMP superfamily protein, ... (5 entities in total)
• Functional Keywords: immune system-rna complex, immune system/rna
• Biological source: Candidatus Scalindua brodae; More
• Total number of polymer chains: 4
• Total formula weight: 313370.89

Authors

Feng, Y.,Zhang, L. (deposition date: 2022-05-16, release date: 2022-11-09, Last modification date: 2024-07-03)

Primary citation

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.
Target RNA activates the protease activity of Craspase to confer antiviral defense.
Mol.Cell, 82:4503-4518.e8, 2022

PubMed 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.

PubMed: 36306795
DOI: 10.1016/j.molcel.2022.10.007

Experimental method

ELECTRON MICROSCOPY (3.08 Å)