Ribosomal stalk-captured CARF-RelE ribonuclease inhibits translation following CRISPR signaling.
basic_science · Level V
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- Record sourced from PubMed, PMID 38033086.
- Also identified by DOI 10.1126/science.adj2107.
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Abstract
Prokaryotic type III CRISPR-Cas antiviral systems employ cyclic oligoadenylate (cA<sub>n</sub>) signaling to activate a diverse range of auxiliary proteins that reinforce the CRISPR-Cas defense. Here we characterize a class of cA<sub>n</sub>-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 (cA<sub>4</sub>), 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-cA<sub>4</sub> 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.
Medical subject headings
- Bacteria
- Bacterial Proteins
- CRISPR-Associated Proteins
- CRISPR-Cas Systems
- Endoribonucleases