vapB36 Resolved · high auto-curated

H37Rv Rv1982A · MTBC0 - · 86 aa · 2225841–2226101 (-) · RefSeq YP_004837054.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)antitoxin VapB36
MTBC0 PGAP re-annotation
Revised (this work)Antitoxin VapB36. 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.

Annotated on the H37Rv protein: this gene has no 1:1 ancestral MTBC0 anchor (PE/PPE, paralogue, IS element, or otherwise unanchored CDS).

Curated reference (UniProt)

UniProt P9WJ29 SwissProt · reviewed · Evidence at protein level
UniProt namePutative antitoxin VapB36
Curated functionPossibly the antitoxin component of a type II toxin-antitoxin (TA) system. Its cognate toxin is VapC36.

UniProt still lists this protein as Putative antitoxin VapB36; the revised annotation above is ahead of the current UniProt record.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category S Function unknown
eggNOG descriptionTranscription factor
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, 1 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 1.4e-181–72 Rv0623-like transcription factor

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

Closest characterised functional partner: vapC36 (ribonuclease VapC36), high confidence from genomic context alone (score 926 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv1982c vapC36 ribonuclease VapC36 986 926 ctx neighborhood:882 textmining:828
Rv1983 PE_PGRS35 PE-PGRS family protein PE_PGRS35 535 535 ctx neighborhood:535
Rv1981c nrdF1 ribonucleoside-diphosphate reductase subunit beta NrdF1 443 443 ctx neighborhood:443
Rv2759c vapC42 ribonuclease VapC42 464 430
Rv0609 vapC28 ribonuclease VapC28 464 430
Rv1741 vapC34 ribonuclease VapC34 464 430
Rv0624 vapC30 ribonuclease VapC30 464 430
Rv1969 mce3D Mce family protein Mce3D 880 41 textmining:881
Rv1970 lprM Mce family lipoprotein LprM 819 41 textmining:819
Rv0595c vapC4 ribonuclease VapC4 800 41 textmining:800

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

  • Annotation from H37Rv (no MTBC0 1:1 anchor; H37Rv protein used): antitoxin VapB36
  • Pfam (hmmscan --cut_ga): PSK_trans_fac PF07704.18 (E=1e-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 YP_004837054.1)
  • 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 P9WJ29 (SwissProt, reviewed; Evidence at protein level)
  • 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 — 10 functional partner(s); context anchor vapC36
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv1982A|vapB36
MALNIKDPEVDRLAAELADRLHTSKTAAIRHALSAQLAFLESRAGDREAQLLDILRTEIWPLLADRSPITKLEREQILGYDPATGV