vapB34 Family assigned · medium auto-curated

H37Rv Rv1740 · MTBC0 mtbc0_001853 · 70 aa · 1979777–1979989 (+) · RefSeq NP_216256.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)antitoxin VapB34
MTBC0 PGAP re-annotationtype II toxin-antitoxin system VapB family antitoxin
Revised (this work)Type II toxin-antitoxin system VapB family antitoxin. Pfam: PSK_trans_fac (PF07704.18).

Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.

Curated reference (UniProt)

UniProt P9WJ31 SwissProt · reviewed · Predicted
UniProt namePutative antitoxin VapB34
Curated functionAntitoxin component of a possible type II toxin-antitoxin (TA) system. The cognate toxin is VapC34.

UniProt still lists this protein as Putative antitoxin VapB34; the revised annotation above is ahead of the current UniProt record.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category S Function unknown
Preferred namevapB30
eggNOG descriptionpositive regulation of growth
Orthologous groupCOG4423
KEGG orthology K19687

Orthology-based transfer (eggNOG 5.0.2, diamond). EC/KO/GO/CAZy are computed annotations, not manual curation; cross-check against the primary literature before treating a specific reaction as established.

Conservation & selection (intra-MTBC, 145 209 strains)

pN/pS n/a
Polymorphic sites (≥ 0.1% of strains) 0 synonymous, 3 missense, 0 nonsense, 0 frameshift

pN/pS from segregating SNPs (singletons removed) normalised by possible sites. Low pN/pS = purifying selection (a strong signal that a "hypothetical" is a real, constrained gene). A high pN/pS is ambiguous: relaxed constraint or positive selection (drug resistance, antigenic variation) inflate it; e.g. rpoB/katG/pncA score high here for resistance, not loss of function. A clonal disruption (one allele over a clade) suggests lineage pseudogenisation; a convergent one (many independent alleles) is typical of resistance loss-of-function.

Domains (Pfam, hmmscan --cut_ga)

PfamAccessioni-EvalueResiduesDescription
PSK_trans_facPF07704.18 4.5e-182–69 Rv0623-like transcription factor

Functional interaction network (STRING v12, guilt-by-association)

Closest characterised functional partner: vapC34 (ribonuclease VapC34), high confidence from genomic context alone (score 970 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv1741 vapC34 ribonuclease VapC34 972 970 ctx neighborhood:801 experimental:853
Rv0624 vapC30 ribonuclease VapC30 943 898 experimental:853 textmining:467
Rv3291c lrpA transcriptional regulator LrpA 797 797 coexpression:797
Rv1742 hyp hypothetical protein 786 785 ctx neighborhood:780
Rv0273c transcriptional regulator 783 783 coexpression:783
Rv2759c vapC42 ribonuclease VapC42 792 769 experimental:754
Rv0609 vapC28 ribonuclease VapC28 785 763 experimental:754
Rv1982c vapC36 ribonuclease VapC36 784 762 experimental:754
Rv3488 hyp hypothetical protein 761 761 coexpression:761
Rv2788 sirR transcriptional repressor SirR 744 744 coexpression:744
Rv1267c embR transcriptional regulator EmbR 738 738 coexpression:738
Rv3328c sigJ ECF RNA polymerase sigma factor SigJ 734 734 coexpression:734
Rv1960c parD1 antitoxin ParD1 751 733 coexpression:733
Rv0117 oxyS oxidative stress response regulatory protein OxyS 733 733 coexpression:733
Rv1033c trcR two component transcriptional regulator TrcR 732 732 coexpression:732

STRING combines evidence channels (neighborhood, fusion, cooccurrence, coexpression, experimental, database, text-mining) into a 0–1000 score. The ctx badge marks edges carried by the genomic-context channels (conserved neighborhood, fusion, phylogenetic co-occurrence), which are independent of orthology and structure and the strongest signal for an unknown gene. The no text-mining column recomputes the score from data alone, so a link that does not depend on the literature is visible. Association is a function hypothesis, not proof: corroborate with the operon context and the primary literature before assigning a function.

Evidence

  • Legacy H37Rv annotation: antitoxin VapB34
  • MTBC0 PGAP product: type II toxin-antitoxin system VapB family antitoxin
  • Pfam (hmmscan --cut_ga): PSK_trans_fac PF07704.18 (E=4e-18)
  • (auto-curated by rules from PGAP + Pfam + Foldseek; not hand-reviewed)

Sources

  • Ancestral sequence & coordinates: Harrison LB et al. (2024), An imputed ancestral reference genome for the MTBC, doi:10.1101/2023.09.07.556366
  • Product annotation: NCBI PGAP on MTBC0; legacy from H37Rv NC_000962.3 (RefSeq NP_216256.1)
  • Domains: Pfam-A via hmmscan --cut_ga — PSK_trans_fac (PF07704.18)
  • Sequence-level signal: ESM Atlas (EvolutionaryScale × BioHub) — exploratory
  • Controlled vocabulary: eggNOG-mapper 2.1.12 (Cantalapiedra et al. 2021, doi:10.1093/molbev/msab293), eggNOG 5.0 DB (Huerta-Cepas et al. 2019) — OG COG4423
  • Curated reference: UniProt P9WJ31 (SwissProt, reviewed; Predicted)
  • Intra-MTBC selection: pN/pS and disruption from SPDI variants of 145 209 MTBC strains (this work, local collection vs H37Rv NC_000962.3)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 55 functional partner(s); context anchor vapC34
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_001853|Rv1740|vapB34
MELAARMGETLTQAVVVAVREQLARRTGRTRSISLREELAAIGRRCAALPVLDTRAADTILGYDERGLPA