Mok-Hok-Sok system

traitmech:000372 · CLASS · PROPOSED

A phage defense system in which an organism possesses a hok/sok toxin-antitoxin locus represented by DefenseFinder as the two-profile Mok_Hok_Sok model and experimentally linked to bacteriophage T4 exclusion by the plasmid R1 hok/sok locus.

Trait evidence (7)

PMID:8606182
To investigate whether the hok/sok locus evolved as a phage-exclusion mechanism, Escherichia coli cells that contain hok/sok on a pBR322-based plasmid were challenged with T1, T4, T5, T7, and lambda phage.

Pecota and Wood tested whether a plasmid-carried hok/sok locus can act as a phage-exclusion mechanism.
PMID:8606182
The presence of hok/sok reduced the efficiency of plating of T4 by 42% and decreased the plaque size by approximately 85%.

Pecota and Wood show that hok/sok reduced bacteriophage T4 plating efficiency and plaque size.
PMID:8606182
Single-step growth experiments demonstrated that hok/sok decreased the T4 burst size by 40%, increased the time to form mature phage (eclipse time) from 22 to 30 min, and increased the time to cell lysis (latent period) from 30 to 60 min.

Pecota and Wood support delayed T4 development and a lower T4 burst size in the presence of hok/sok.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1

The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv
Mok_Hok_Sok Mok_Hok_Sok 1 1 Mok_Hok_Sok__Hok, Mok_Hok_Sok__Mok

The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| Mok_Hok_Sok__Hok | Mok_Hok_Sok__Hok | Mok_Hok_Sok | Custom | 90 |

The DefenseFinder HMM inventory records Mok_Hok_Sok__Hok under Mok_Hok_Sok.
https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
| Mok_Hok_Sok__Mok | Mok_Hok_Sok__Mok | Mok_Hok_Sok | Custom | 20 |

The DefenseFinder HMM inventory records Mok_Hok_Sok__Mok under Mok_Hok_Sok.

Mok-Hok-Sok loci exclude T4 phage

Conservative system-level sketch linking a DefenseFinder Mok_Hok_Sok locus to bacteriophage T4 exclusion and the Mok-Hok-Sok system trait.

NONMECHANISTIC · The graph captures Mok_Hok_Sok as a named DefenseFinder two-profile model tied to plasmid R1 hok/sok T4 exclusion while leaving natural host breadth, Sok antisense-RNA representation, Hok toxin activation, and the exact DefenseFinder Hok/Mok profile-to-activity mapping unresolved.

Edge evidence

Mok_Hok_Sok locus contributes to T4 phage exclusion RO:0002326
The plasmid R1 hok/sok locus can mediate T4 phage exclusion, and DefenseFinder models Mok_Hok_Sok as a Hok/Mok two-profile system.
- PMID:8606182 The presence of hok/sok reduced the efficiency of plating of T4 by 42% and decreased the plaque size by approximately 85%. Pecota and Wood connect hok/sok possession to bacteriophage T4 restriction.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv Mok_Hok_Sok Mok_Hok_Sok 1 1 Mok_Hok_Sok__Hok, Mok_Hok_Sok__Mok The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | Mok_Hok_Sok__Hok | Mok_Hok_Sok__Hok | Mok_Hok_Sok | Custom | 90 | The DefenseFinder HMM inventory records Mok_Hok_Sok__Hok under Mok_Hok_Sok.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md | Mok_Hok_Sok__Mok | Mok_Hok_Sok__Mok | Mok_Hok_Sok | Custom | 20 | The DefenseFinder HMM inventory records Mok_Hok_Sok__Mok under Mok_Hok_Sok.
T4 phage exclusion confers Mok-Hok-Sok system METPO:2007700
T4 phage exclusion realizes the Mok-Hok-Sok system trait.
- PMID:8606182 Single-step growth experiments demonstrated that hok/sok decreased the T4 burst size by 40%, increased the time to form mature phage (eclipse time) from 22 to 30 min, and increased the time to cell lysis (latent period) from 30 to 60 min. Pecota and Wood show lower burst size and delayed T4 development when hok/sok is present.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1 The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper.
Mok-Hok-Sok system is a phage defense system rdfs:subClassOf
Mok-Hok-Sok system possession is a phage-defense-system trait.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1 The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper.
- https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv Mok_Hok_Sok Mok_Hok_Sok 1 1 Mok_Hok_Sok__Hok, Mok_Hok_Sok__Mok The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds.

Provenance

Identifier source: TraitMech local identifier
Definition source: DOI:10.1128/jb.178.7.2044-2050.1996

Parent traits (1)

phage defense system traitmech:000209

Synonyms (4)

Mok_Hok_Sok RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md
hok/sok RELATED_SYNONYM · PMID:8606182
Mok_Hok_Sok__Hok RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md
Mok_Hok_Sok__Mok RELATED_SYNONYM · https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md

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 the natural host range, Sok antisense-RNA representation, Hok toxin activation, and Hok/Mok profile-to-activity mapping before minting narrower Mok-Hok-Sok mechanism children.

KNOWLEDGE GAP OPEN mok-hok-sok-natural-context-gap · raised by codex · 2026-09-25

Attached to causal_graphs#mok_hok_sok_locus_restricts_t4_phage

Pecota and Wood support T4 exclusion by the plasmid R1 hok/sok locus carried on a pBR322-based plasmid, and DefenseFinder models Mok_Hok_Sok with Hok and Mok protein profiles. This first record leaves the native biological breadth, RNA antitoxin representation, Hok triggering, and profile-to-activity mapping unresolved.

Curation history

2026-09-25T05:02:42Z · MINTED_TRAITMECH_ID · codex
Minted Mok-Hok-Sok 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_v249.