TopAI-YjhQ toxin-antitoxin neutralization

A protein-sequestration module for the Escherichia coli topAI-yjhQ toxin-antitoxin pair in which YjhQ acts as the antitoxin for TopAI/YjhX. YjhQ binding neutralizes TopAI toxicity and relieves TopAI-mediated inhibition of topoisomerase I. YjhQ's predicted GNAT-family acetyltransferase chemistry remains substrate-unknown and is outside this toxin-sequestering module.

MODULE:topai_yjhq_toxin_antitoxinDRAFTCONCRETERegulatory Stepmodules/topai_yjhq_toxin_antitoxin.yaml
TopAI-YjhQ toxin-antitoxin neutralization
GO:0097351
toxin sequestering activity
Defines the protein-binding antitoxin activity of YjhQ.
file:genes/ECOLI/yjhQ/yjhQ-ai-review.yaml
ECOLI yjhQ gene review
The completed E. coli yjhQ review grounds YjhQ as the antitoxin that sequesters TopAI/YjhX.
PMID:26553797
An endogenous protein inhibitor, YjhX (TopAI), for topoisomerase I from Escherichia coli.
Establishes the topAI-yjhQ pair, YjhQ neutralization of TopAI toxicity, and physical TopAI-YjhQ interaction.
co-induction of YjhQ in the presence of 0.2% arabinose with TopAI in the presence of 0.1 mM IPTG neutralized the toxicity of TopAI indicating that the overproduction of TopAI is toxic to the cells, while YjhQ is the antitoxin for TopAI
PMID:26553797
An endogenous protein inhibitor, YjhX (TopAI), for topoisomerase I from Escherichia coli.
Shows that YjhQ physically complexes with TopAI and relieves TopAI inhibition of topoisomerase I.
PrS2-YjhQ was pulled down with PrS-TopAI (Figure 1B; lanes 9 and 10) but not with PrS (Figure 1B; lanes 4 and 5), indicating that TopAI toxin interacts with YjhQ antitoxin in a manner similar to that of other TA systems.

TopAI/YjhX is modeled only at the TopAI-YjhQ boundary needed to describe the reviewed YjhQ antitoxin; a full TopAI/topoisomerase-I inhibition review should wait for dedicated TopAI curation.

1Nodes
0Parts
0Variant Sets
0Variants
2Annotons
1Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:topai_yjhq_toxin_antitoxin deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

1 gene-function check(s) reflected in core functions · 0 conflict(s) · 1 evidence or coverage gap(s) (2 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
topai_topa_inhibitor E. coli TopAI/YjhX
UniProtKB:Q2EEU2
Gene
topoisomerase I inhibitor activity
No function ID
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. The module function also lacks a GO identifier.
yjhq_topai_antitoxin E. coli YjhQ
UniProtKB:P39368
Gene
toxin sequestering activity
GO:0097351
Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).

Feedback loops (advisory, prose-driven: a regulator counts as "feedback" when its own description says so)

✓ every negative regulator described as feedback has an upstream edge closing the loop.

  • yjhq_topai_antitoxin ⊣ topai_topa_inhibitor [input]
    yjhq_topai_antitoxin is a negative regulator with no upstream edge (not described as feedback)

Gene-review completeness (1/2 grounded genes reviewed)

1 complete review(s) · 1 with deep research · 1 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
E. coli TopAI/YjhX Q2EEU2 ✗ — —
yjhQ P39368 ✓ ✓ ✓

Details

Context
Escherichia coliNCBITaxon:83333
TopAI-YjhQ toxin-antitoxin neutralizationRegulatory Steptopai_yjhq_toxin_antitoxin
TopAI-YjhQ toxin-antitoxin neutralization
Context
Escherichia coliNCBITaxon:83333

Annotons

TopAI topoisomerase I inhibitor
topai_topa_inhibitor
Participant: Gene Product: E. coli TopAI/YjhX
Gene Product:
E. coli TopAI/YjhXUniProtKB:Q2EEU2

Function

topoisomerase I inhibitor activity
Targets: DNA topoisomerase I (TopA)

Toxin that inhibits DNA topoisomerase I, causing DNA/RNA synthesis defects and growth arrest when overproduced.

YjhQ TopAI antitoxin
yjhq_topai_antitoxin
Participant: Gene Product: E. coli YjhQ
Gene Product:
E. coli YjhQUniProtKB:P39368

Function

toxin sequestering activityGO:0097351
Targets: TopAI/YjhX toxin

Antitoxin that physically binds TopAI and neutralizes its inhibition of topoisomerase I.

Connections

YjhQ binds and sequesters TopAI, relieving TopAI inhibition of DNA topoisomerase I.
PMID:26553797
An endogenous protein inhibitor, YjhX (TopAI), for topoisomerase I from Escherichia coli.
Purified YjhQ counteracted TopAI-mediated topoisomerase I inhibition.
The addition of PrS2-YjhQ rescued topoisomerase I activity in a dose-dependent manner