identifier: traitmech:000372 label: Mok-Hok-Sok system definition: 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. definition_source: DOI:10.1128/jb.178.7.2044-2050.1996 trait_category: GENOMICS term_kind: CLASS mapping_status: PROPOSED parent_traits: - traitmech:000209 synonyms: - synonym_text: Mok_Hok_Sok synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md - synonym_text: hok/sok synonym_type: RELATED_SYNONYM source: PMID:8606182 - synonym_text: Mok_Hok_Sok__Hok synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md - synonym_text: Mok_Hok_Sok__Mok synonym_type: RELATED_SYNONYM source: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md evidence: - reference: PMID:8606182 snippet: 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. notes: Pecota and Wood tested whether a plasmid-carried hok/sok locus can act as a phage-exclusion mechanism. - reference: PMID:8606182 snippet: The presence of hok/sok reduced the efficiency of plating of T4 by 42% and decreased the plaque size by approximately 85%. notes: Pecota and Wood show that hok/sok reduced bacteriophage T4 plating efficiency and plaque size. - reference: PMID:8606182 snippet: 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. notes: Pecota and Wood support delayed T4 development and a lower T4 burst size in the presence of hok/sok. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1 notes: The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Mok_Hok_Sok\tMok_Hok_Sok\t1\t1\tMok_Hok_Sok__Hok, Mok_Hok_Sok__Mok\t\t\ \t" notes: The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Mok_Hok_Sok__Hok | Mok_Hok_Sok__Hok | Mok_Hok_Sok | Custom | 90 |' notes: The DefenseFinder HMM inventory records Mok_Hok_Sok__Hok under Mok_Hok_Sok. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Mok_Hok_Sok__Mok | Mok_Hok_Sok__Mok | Mok_Hok_Sok | Custom | 20 |' notes: The DefenseFinder HMM inventory records Mok_Hok_Sok__Mok under Mok_Hok_Sok. causal_graphs: - graph_id: mok_hok_sok_locus_restricts_t4_phage title: Mok-Hok-Sok loci exclude T4 phage description: Conservative system-level sketch linking a DefenseFinder Mok_Hok_Sok locus to bacteriophage T4 exclusion and the Mok-Hok-Sok system trait. scope_status: NONMECHANISTIC scope_notes: 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. nodes: - node_id: mok_hok_sok_locus label: Mok_Hok_Sok locus node_type: GENETIC_ELEMENT description: A hok/sok toxin-antitoxin phage-defense locus represented by the DefenseFinder Mok_Hok_Sok Hok and Mok profiles. - node_id: t4_phage_exclusion label: T4 phage exclusion node_type: BIOLOGICAL_PROCESS description: Restriction of bacteriophage T4 plaque formation, burst size, and lysis timing in a host carrying hok/sok. - node_id: mok_hok_sok_system_trait label: Mok-Hok-Sok system node_type: TRAIT grounding: traitmech:000372 description: Possession of a genome-encoded Mok-Hok-Sok phage-defense system. - node_id: phage_defense_system label: phage defense system node_type: TRAIT grounding: traitmech:000209 description: Possession of one or more genome-encoded immune systems that inhibit bacteriophage infection. edges: - subject: mok_hok_sok_locus predicate: contributes to predicate_id: RO:0002326 object: t4_phage_exclusion description: The plasmid R1 hok/sok locus can mediate T4 phage exclusion, and DefenseFinder models Mok_Hok_Sok as a Hok/Mok two-profile system. evidence: - reference: PMID:8606182 snippet: The presence of hok/sok reduced the efficiency of plating of T4 by 42% and decreased the plaque size by approximately 85%. notes: Pecota and Wood connect hok/sok possession to bacteriophage T4 restriction. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Mok_Hok_Sok\tMok_Hok_Sok\t1\t1\tMok_Hok_Sok__Hok, Mok_Hok_Sok__Mok\t\ \t\t" notes: The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Mok_Hok_Sok__Hok | Mok_Hok_Sok__Hok | Mok_Hok_Sok | Custom | 90 |' notes: The DefenseFinder HMM inventory records Mok_Hok_Sok__Hok under Mok_Hok_Sok. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/Liste_hmm_system.md snippet: '| Mok_Hok_Sok__Mok | Mok_Hok_Sok__Mok | Mok_Hok_Sok | Custom | 20 |' notes: The DefenseFinder HMM inventory records Mok_Hok_Sok__Mok under Mok_Hok_Sok. - subject: t4_phage_exclusion predicate: confers predicate_id: METPO:2007700 object: mok_hok_sok_system_trait description: T4 phage exclusion realizes the Mok-Hok-Sok system trait. evidence: - reference: PMID:8606182 snippet: 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. notes: Pecota and Wood show lower burst size and delayed T4 development when hok/sok is present. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1 notes: The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper. - subject: mok_hok_sok_system_trait predicate: is a predicate_id: rdfs:subClassOf object: phage_defense_system description: Mok-Hok-Sok system possession is a phage-defense-system trait. evidence: - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/List_system_article.md snippet: Mok_Hok_Sok | 10\.1128/jb\.178\.7\.2044-2050\.1996 | Exclusion of T4 phage by the hok/sok killer locus from plasmid R1 notes: The DefenseFinder article registry maps the named Mok_Hok_Sok system to the Pecota and Wood plasmid R1 hok/sok phage-exclusion paper. - reference: https://raw.githubusercontent.com/mdmparis/defense-finder-models/afb0e5a8b466be53586b13266f5d38d98c3ac268/DefenseFinder_rules.tsv snippet: "Mok_Hok_Sok\tMok_Hok_Sok\t1\t1\tMok_Hok_Sok__Hok, Mok_Hok_Sok__Mok\t\ \t\t" notes: The DefenseFinder rules table models Mok_Hok_Sok as a single system listing Hok and Mok profiles with 1/1 thresholds. discussions: - discussion_id: mok-hok-sok-natural-context-gap prompt: 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. kind: KNOWLEDGE_GAP status: OPEN rationale: 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. attaches_to: - causal_graphs#mok_hok_sok_locus_restricts_t4_phage posed_by: codex posed_date: '2026-09-25' curation_history: - timestamp: '2026-09-25T05:02:42Z' curator: codex action: MINTED_TRAITMECH_ID changes: 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. llm_assisted: true