{
  "abstract": "Cyclic oligoadenylate (cOA) secondary messengers are generated by type III CRISPR systems in response to viral infection. cOA allosterically activates the CRISPR ancillary ribonucleases Csx1/Csm6, which degrade RNA non-specifically using a HEPN (Higher Eukaryotes and Prokaryotes, Nucleotide binding) active site. This provides effective immunity but can also lead to growth arrest in infected cells, necessitating a means to deactivate the ribonuclease once viral infection has been cleared. In the crenarchaea, dedicated ring nucleases degrade cA 4 (cOA consisting of 4 AMP units), but the equivalent enzyme has not been identified in bacteria. We demonstrate that, in Thermus thermophilus HB8 , the uncharacterized protein TTHB144 is a cA 4 -activated HEPN ribonuclease that also degrades its activator. TTHB144 binds and degrades cA 4 at an N-terminal CARF (CRISPR-associated Rossman fold) domain. The two activities can be separated by site-directed mutagenesis. TTHB144 is thus the first example of a self-limiting CRISPR ribonuclease.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "name": "Januka Athukoralage"
    },
    {
      "name": "Shirley Graham"
    },
    {
      "name": "Sabine Grüschow"
    },
    {
      "name": "Christophe Rouillon"
    },
    {
      "name": "Malcolm White"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5tsa4gqqf0pb9.bib",
  "cited_by": 78,
  "doi": "10.1016/j.jmb.2019.04.041",
  "fulltext_url": null,
  "id": "5tsa4gqqf0pb9",
  "issns": [
    "0022-2836",
    "1089-8638"
  ],
  "landing_url": "https://hal.science/hal-05769444v1",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "hal",
      "0.sdv"
    ],
    [
      "openalex",
      "1312|CRISPR and Genetic Engineering"
    ]
  ],
  "openalex": "W2951567133",
  "pdf_url": "https://ars.els-cdn.com/content/image/1-s2.0-S0022283619302499-ga1_lrg.jpg",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-29",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/5tsa4gqqf0pb9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:43Z",
      "native_id": "hal-05769444",
      "source": "hal",
      "url": "https://hal.science/hal-05769444v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "openalex:1312|CRISPR and Genetic Engineering",
      "subfield": "molecular-biology"
    }
  ],
  "title": "A Type III CRISPR Ancillary Ribonuclease Degrades Its Cyclic Oligoadenylate Activator",
  "title_text": "A Type III CRISPR Ancillary Ribonuclease Degrades Its Cyclic Oligoadenylate Activator",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:17:43Z",
  "url": "https://research.draconitic.com/paper/5tsa4gqqf0pb9",
  "venue": "Journal of Molecular Biology",
  "versions": []
}