id: P39368
gene_symbol: yjhQ
locus_tag: b4307
taxon:
  id: NCBITaxon:83333
  label: Escherichia coli K-12
status: COMPLETE
description: >-
  YjhQ DeepECTF prediction review. The DeepECTF prediction of mycothiol synthase
  (EC 2.3.1.189) is incorrect. Mycothiol is not synthesized by E. coli, and the
  remaining pathway enzymes are absent from the genome. YjhQ is actually an antitoxin
  component of the TopAI-YjhQ toxin-antitoxin system.
references:
  - id: PMID:37963869
    title: Functional annotation of enzyme-encoding genes using deep learning with transformer layers.
  - id: PMID:40703034
    title: Limitations of current machine learning models in predicting enzymatic functions for uncharacterized
      proteins.
predictions:
  - source_method: DeepECTF
    source_version: "2023"
    source_reference_id: PMID:37963869
    predicted_term:
      id: EC:2.3.1.189
      label: mycothiol synthase
    predicted_term_type: EC
    review:
      assessment: NPI
      confidence_score: 0
      error_type: PATHWAY_CONTEXT_IGNORED
      summary: >-
        Nonparalog incorrect. Mycothiol is not a molecule synthesized by E. coli.
        The mycothiol biosynthesis pathway (BioCyc ID: PWY1G-0) is absent from E. coli -
        none of the other pathway enzymes are encoded in the genome. Mycothiol is produced
        by Actinobacteria (e.g., Mycobacterium). YjhQ is actually an N-acetyltransferase
        that functions as an antitoxin in the TopAI-YjhQ type IV toxin-antitoxin system,
        sequestering the TopAI toxin to prevent translation inhibition.
      supported_by:
        - reference_id: PMID:40703034
          supporting_text: "YjhQ/b4307 is predicted to be a mycothiol synthase (EC 2.3.1.189), but mycothiol is not a molecule synthesized by E. coli, and the remaining pathway genes are absent from the genome (BioCyc ID: PWY1G-0)"