Hesat system

traitmech:000327 · CLASS · PROPOSED

A phage defense system in which an organism possesses a Hesat locus that can restrict bacteriophage infection.

Trait evidence (4)

DOI:10.1093/nar/gkae671
Based on comparative sequence analysis (BLASTN and BLASTP) and on functional and structural analysis (HHpred and InterPro) the remaining seven antiphage systems (out of the twenty identified) did not display significant homology to any previously described antiphage system, thus rendering them novel antiphage systems (Table 1). These systems were named after cheese, cattle or fermentation related deities (Rhea, Aristaios, Kamadhenu, Fliodhais, Audmula, Rugutis and Hesat)

Grafakou et al. named Hesat among seven not previously described lactococcal antiphage systems.
DOI:10.1093/nar/gkae671
Except for Hesat, which was cloned in pPTPi with the addition of its native signals, all novel systems were cloned in the high-copy number vector pNZ44 (Supplementary Table S2). All discovered systems, except Fliodhais, are single gene antiphage systems.

Grafakou et al. identify Hesat as a single-gene novel antiphage system cloned with native signals in pPTPi.
DOI:10.1093/nar/gkae671
For Hesat, no domain was predicted by HHpred and InterPro. Dali analysis reports significant hits with the colicin-D toxic domain (PDB ID 1V74; Figure 4N, O), which specifically cleaves the anticodon loop of all four tRNA(Arg) iso-acceptors, thereby resulting in cell death (68). Therefore, it is proposed that Hesat upon phage infection is activated to block translation, which is in accordance with its abortive infection phenotype.

Grafakou et al. report that Hesat had no HHpred or InterPro domain prediction, and they propose a colicin-D-like translation-blocking activity upon phage infection.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
Hesat | 10\.1093/nar/gkae671 | Discovery of antiphage systems in the lactococcal plasmidome

The DefenseFinder article registry maps the named Hesat system to the Grafakou et al. lactococcal antiphage-system discovery paper.

Hesat loci confer bacterial phage defense

Conservative system-level sketch linking possession of a Hesat locus to restricted bacteriophage propagation without asserting the unresolved phage trigger or molecular output.

NONMECHANISTIC · The graph captures Hesat as a named single-gene lactococcal anti-phage system while leaving its direct phage trigger, molecular substrate, experimentally validated antiviral effector output, natural locus breadth, and the absence of pinned DefenseFinder HMM or rule rows unresolved.

Edge evidence

Hesat locus contributes to restricted phage propagation RO:0002326
The lactococcal plasmidome screen discovered Hesat as a named single-gene antiphage system, and the DefenseFinder article registry maps the Hesat system to that discovery paper.
- DOI:10.1093/nar/gkae671 Based on comparative sequence analysis (BLASTN and BLASTP) and on functional and structural analysis (HHpred and InterPro) the remaining seven antiphage systems (out of the twenty identified) did not display significant homology to any previously described antiphage system, thus rendering them novel antiphage systems (Table 1). These systems were named after cheese, cattle or fermentation related deities (Rhea, Aristaios, Kamadhenu, Fliodhais, Audmula, Rugutis and Hesat) Grafakou et al. named Hesat as one of the novel lactococcal antiphage systems.
- DOI:10.1093/nar/gkae671 Except for Hesat, which was cloned in pPTPi with the addition of its native signals, all novel systems were cloned in the high-copy number vector pNZ44 (Supplementary Table S2). All discovered systems, except Fliodhais, are single gene antiphage systems. Grafakou et al. identify Hesat as a single-gene antiphage system.
- DOI:10.1093/nar/gkae671 For Hesat, no domain was predicted by HHpred and InterPro. Dali analysis reports significant hits with the colicin-D toxic domain (PDB ID 1V74; Figure 4N, O), which specifically cleaves the anticodon loop of all four tRNA(Arg) iso-acceptors, thereby resulting in cell death (68). Therefore, it is proposed that Hesat upon phage infection is activated to block translation, which is in accordance with its abortive infection phenotype. Grafakou et al. propose that Hesat blocks translation after phage infection while leaving that molecular output unresolved.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md Hesat | 10\.1093/nar/gkae671 | Discovery of antiphage systems in the lactococcal plasmidome The DefenseFinder article registry maps the named Hesat system to the Grafakou et al. lactococcal antiphage-system discovery paper.
restricted phage propagation confers Hesat system METPO:2007700
Hesat-mediated phage restriction realizes the Hesat system trait.
- DOI:10.1093/nar/gkae671 For Hesat, no domain was predicted by HHpred and InterPro. Dali analysis reports significant hits with the colicin-D toxic domain (PDB ID 1V74; Figure 4N, O), which specifically cleaves the anticodon loop of all four tRNA(Arg) iso-acceptors, thereby resulting in cell death (68). Therefore, it is proposed that Hesat upon phage infection is activated to block translation, which is in accordance with its abortive infection phenotype. Grafakou et al. treat Hesat as having an abortive infection phenotype and propose a translation-blocking mechanism upon phage infection.
Hesat system is a phage defense system rdfs:subClassOf
Hesat system possession is a phage-defense-system trait.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md Hesat | 10\.1093/nar/gkae671 | Discovery of antiphage systems in the lactococcal plasmidome The DefenseFinder article registry maps the named Hesat system to the Grafakou et al. lactococcal antiphage-system discovery paper.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1093/nar/gkae671

Parent traits (1)

phage defense system traitmech:000209

Synonyms (1)

Hesat EXACT_SYNONYM · DOI:10.1093/nar/gkae671

kg-microbe context

No kg-microbe node embedding matched this record in the 2026-04-25 deepwalk.

Discussions and Knowledge Gaps (1)

Open questions attached to this trait. Seeded by just knowledge-gap-scan and curated; see the corpus-wide index.

Resolve Hesat phage triggers and effector outputs before minting narrower Hesat mechanism children.

KNOWLEDGE GAP OPEN hesat-mechanism-gap · raised by codex · 2026-09-21

Attached to causal_graphs#hesat_locus_restricts_phage

Grafakou et al. and DefenseFinder support Hesat as a named single-gene anti-phage system, but the direct trigger, experimentally validated molecular substrate, antiviral effector output, natural locus breadth, and profile-to-component model are not resolved enough here to assert a narrower mechanistic child trait.

Curation history

2026-09-21T04:55:54Z · MINTED_TRAITMECH_ID · codex
Minted Hesat system as a DOI-backed GENOMICS TraitRecord under phage defense system after an ignored-and-hidden duplicate review found no exact live TraitMech, METPO, history, or prior proposal record; the replacement placeholder is reserved in proposals/metpo_traitmech_v204.