8PHB image
Entry Detail
PDB ID:
8PHB
Keywords:
Title:
Crystal structure of apo Cami1
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-06-19
Release Date:
2023-12-13
Method Details:
Experimental Method:
Resolution:
1.70 Å
R-Value Free:
0.21
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:CRISPR-associated protein, APE2256 family
Chain IDs:A, B
Chain Length:406
Number of Molecules:2
Biological Source:Allochromatium vinosum
Primary Citation
Ribosomal stalk-captured CARF-RelE ribonuclease inhibits translation following CRISPR signaling.
Science 382 1036 1041 (2023)
PMID: 38033086 DOI: 10.1126/science.adj2107

Abstact

Prokaryotic type III CRISPR-Cas antiviral systems employ cyclic oligoadenylate (cAn) signaling to activate a diverse range of auxiliary proteins that reinforce the CRISPR-Cas defense. Here we characterize a class of cAn-dependent effector proteins named CRISPR-Cas-associated messenger RNA (mRNA) interferase 1 (Cami1) consisting of a CRISPR-associated Rossmann fold sensor domain fused to winged helix-turn-helix and a RelE-family mRNA interferase domain. Upon activation by cyclic tetra-adenylate (cA4), Cami1 cleaves mRNA exposed at the ribosomal A-site thereby depleting mRNA and leading to cell growth arrest. The structures of apo-Cami1 and the ribosome-bound Cami1-cA4 complex delineate the conformational changes that lead to Cami1 activation and the mechanism of Cami1 binding to a bacterial ribosome, revealing unexpected parallels with eukaryotic ribosome-inactivating proteins.

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