vapB11 Resolved · high auto-curated

H37Rv Rv1560 · MTBC0 - · 72 aa · 1764755–1764973 H37Rv (+) · RefSeq NP_216076.1

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)antitoxin VapB11
MTBC0 PGAP re-annotation
Revised (this work)Antitoxin VapB11. Pfam: VapB_antitoxin (PF09957.16).
Functional category (TubercuList)virulence, detoxification, adaptation

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).

In the literature (TB corpus sweep) 2 publications

2 TB publications mention this gene. 2 publication(s) discuss this gene (2 in a M. tuberculosis context).

PublicationDate
Toxin-antitoxin system gene mutations driving Mycobacterium tuberculosis transmission revealed by whole genome sequencing. doi:10.3389/fmicb.2024.1398886 2024
Toxin-antitoxin systems shows variability among Mycobacterium tuberculosis lineages. doi:10.1093/femsle/fny276 2019

This layer CITES the literature and adds context; it does not change the verdict or the function stated elsewhere in this fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole): H37Rv locus tag + GENE NAME + ortholog identifiers (Mb…, MMAR_…, MSMEG_…, ML…, MAB_…), under a mycobacterial context filter; hits verified against the abstract text. Species-context counts distinguish M. tuberculosis literature from literature on other mycobacteria. phase76/phase77, 2026-07-13.

Intrinsic disorder (sequence + structure) partially disordered

Predicted disorder36% of residues (metapredict) · mean AlphaFold pLDDT 85.1
Disordered regions1 IDR(s), longest 18 aa [54-72]

carries a substantial disordered region (18/72 residues); disorder is a property, not a function

A property (biophysics), not a function. No LLPS/condensate claim is made from disorder alone. Verdict unchanged. Source: metapredict v3 (Emenecker/Holehouse) per-residue disorder + AlphaFold mean pLDDT (annotation_mtbc P16.13).

CRISPRi vulnerability

Vulnerability index 0.11 (95% CI -2.62 to 3.35). A more negative index = more vulnerable to knockdown (better drug-target quality); indicative threshold VI ≤ -6 = highly vulnerable.

Quantitative CRISPRi knockdown, graded (finer than binary Tn-seq essentiality). Source: CRISPRi vulnerability index (Bosch 2021, pebble.rockefeller.edu).

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb1586 · 98.6% identity
M. orygis RJtmp_001648 · 100.0% identity

Reciprocal-best-hit orthologues (DIAMOND) against the Mycobrowser reference proteomes. A missing species is informative: e.g. a gene absent from M. leprae was likely lost in its reductive genome evolution. Locus tags link to Mycobrowser.

Curated reference (UniProt)

UniProt P9WLU3 SwissProt · reviewed · Evidence at protein level
UniProt nameAntitoxin VapB11
Curated functionAntitoxin component of a type II toxin-antitoxin (TA) system. Upon expression in E.coli and M.smegmatis neutralizes the effect of cognate toxin VapC11.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category K Transcription
eggNOG descriptionBacterial antitoxin of type II TA system, VapB
Orthologous groupCOG5450
Gene Ontology (45) GO:0006417, GO:0008150, GO:0009605, GO:0009607, GO:0009889, GO:0009891, GO:0009893, GO:0010468, GO:0010556, GO:0010557, GO:0010604, GO:0010608 +33 more

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.

Outgroup conservation (beyond the MTBC) Mycobacterium

M. canettii dN/dS (deep-divergence selection) 0.0 (low power) · 1 consensus substitution(s)
low power (1 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 15/53 (28%) · mean identity 52.4% · 3/4 closest MTBAP relatives
present in a subset of the genus (15/53 NTM; in 3 of the 4 closest MTBAP relatives) — partial/intermediate conservation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria

short ORF (72 aa) a shallow stratum may reflect homology-detection failure, not true youth
present across the genus Mycobacterium (NTM) but not detected in any non-Mycobacterium genome — a Mycobacterium-genus gene

Two orthogonal outgroup signals. M. canettii (the immediate outgroup) gives a deep-divergence dN/dS (a low value confirms a constrained, real gene; shown as confident only at ≥8 substitutions, else flagged low-power). Genus-wide presence/absence (tblastn vs assembled non-MTBC genomes) places the gene on the ancient-core ↔ MTBC-specific axis: a gene absent even from the closest MTBAP relatives is a candidate MTBC-specific innovation (possible host-adaptation factor, to confirm by synteny). The phylostratum extends that axis outside the genus (tblastn vs 13 reference genomes spanning Mycobacteriaceae → Corynebacteriales → Actinomycetia → outside the phylum): it is the deepest clade in which a homolog is still detected, i.e. a proxy for gene age. Read it with the null model in mind: a shallow (young) stratum can also reflect homology-detection failure for short or fast-evolving ORFs, so it is a descriptive axis, not a proof of novelty.

Essentiality (transposon mutagenesis)

DeJesus 2017 callNE · non-essential
What the call meansnon-essential
TA sites (Himar1) 3 in the ORF — 0 in the essential state, 0 growth-defect, 3 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 18. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.
CaveatStatistically thin call: only 3 TA (Himar1) sites in the whole ORF (atlas median 13; genes under 300 nt typically have very few). A DeJesus 2017 call built on so few independent observations is less robust than the same call on a longer gene, in either direction. Cross-check against the CRISPRi vulnerability index (independent of TA-site density) and, if this gene overlaps a neighbour (see Genomic-neighbour overlap section below), verify how many of its TA sites actually fall inside its own ORF. (P20.3)

Genome-wide Himar1 transposon essentiality in H37Rv (DeJesus 2017). An essential call (ES/ESD/GD) is strong, independent evidence that a "hypothetical" locus encodes a functional, selectively required gene — orthogonal to intra-species conservation.

Proteomics (mass spectrometry) detected

MS detectiondetected in 7 of 16 independent MS datasets
Integrated abundance26.3 ppm · rank 2146/3519 (39.0th percentile)

Detection by mass spectrometry is direct, experimental evidence that the protein product exists — orthogonal to sequence conservation and to Tn-seq essentiality, and especially decisive for a "hypothetical" locus. Reproducible detection across several independent datasets (PaxDb) makes the existence claim robust; the integrated abundance places the protein in the proteome's dynamic range.

Physico-chemical properties (computed, ProtParam)

Length72 aa
Molecular weight8.2 kDa
Theoretical pI4.85
GRAVY-0.347 (hydrophilic)
Aliphatic index93.5
Aromaticity0.069
Instability index73.5 (unstable)

Computed from the ancestral MTBC0 sequence with the ExPASy ProtParam method (Biopython). Descriptive biophysical context: a positive GRAVY flags a hydrophobic (often membrane) protein, a high instability index (>40) predicts a short in-vitro half-life, an extreme pI hints at compartment or binding partner.

Domains (Pfam, hmmscan --cut_ga)

PfamAccessioni-EvalueResiduesDescription
VapB_antitoxinPF09957.16 1.6e-187–49 Bacterial antitoxin of type II TA system, VapB

Experimental structures (Protein Data Bank) 1 solved

PDBMethodResolutionCoverage
6a7v X-ray diffraction 1.67 Å 86%

Experimentally solved structures mapped from the UniProt accession via PDBe/SIFTS (1 total; up to 8 shown, ranked by sequence coverage then resolution). An experimental structure is direct proof of the folded product and the strongest structural evidence — superseding the predicted ESMFold/AlphaFold models below for any covered region.

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 85.1

PDB hitprobTM-scoreE-valueDescription
6a7v-assembly1_U 1.00 0.60 3.1e-08 sig 6a7v-assembly1_U Crystal structure of Mycobacterium tuberculosis VapBC11 toxin-antitoxin complex
6a7v-assembly1_H 1.00 0.68 1.8e-07 sig 6a7v-assembly1_H Crystal structure of Mycobacterium tuberculosis VapBC11 toxin-antitoxin complex

Foldseek search of the AlphaFold DB model (mean pLDDT 85.1, gated at 70) against the PDB — a genome-wide extension of the ESMFold dark-gene search that also covers proteins beyond the single-sequence length limit. Confident structural neighbours (E < 0.01) shown.

Genomic context (neighbours & predicted operon) operon of 5

Upstream (5' on genome)ilvA (+ strand, 37 bp gap)
Downstream (3' on genome)vapC11 (+ strand, 5 bp gap)
Predicted operon mmpL6 · Rv1558 · ilvA · vapB11 · vapC11

Neighbours from the H37Rv annotation (+ strand). The operon is predicted by co-directional intergenic distance (same strand, gaps ≤50 bp) — a transcription-unit hypothesis, not a mapped TSS. For a "hypothetical", co-transcription with a characterised operon is a concrete functional lead (complements the STRING neighborhood channel below).

Transcriptional regulation (signed TRN: ChIP-seq + TFOE)

Regulated by (2 TF) Rv0135c (represses) · Rv1353c (represses)

Regulatory edges from the ISB signed transcriptional regulatory network (TF ChIP-seq binding, Minch 2015 + TF-overexpression response, Rustad 2014). An edge is regulatory evidence (binding and/or expression change), not necessarily direct. For a "hypothetical", membership in a known regulon (e.g. DosR dormancy, PhoP virulence) is a strong physiological-context lead.

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

Explore full network →

Node colour = verdict, dashed = hypothetical; edge colour = evidence (green experimental, orange genomic-context, grey co-expression), width ∝ score. Click a partner to open its page; "Explore full network" to walk the graph.

Closest characterised functional partner: vapC11 (ribonuclease VapC11), high confidence from genomic context alone (score 1000 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv1561 vapC11 exp ribonuclease VapC11 999 1000 ctx neighborhood:882 cooccurence:703 coexpression:817 experimental:999
Rv2010 vapC15 exp ribonuclease VapC15 961 961 ctx cooccurence:706 experimental:853
Rv1151c cobB NAD-dependent protein deacylase 765 765 coexpression:765
Rv1395 HTH-type transcriptional regulator 733 733 coexpression:733
Rv1960c parD1 antitoxin ParD1 733 733 coexpression:732
Rv3263 DNA methylase 732 732 coexpression:732
Rv0273c transcriptional regulator 731 731 coexpression:731
Rv0624 vapC30 ribonuclease VapC30 685 686 ctx cooccurence:509
Rv1559 ilvA threonine dehydratase IlvA 667 667 ctx neighborhood:659
Rv0158 transcriptional regulator 651 651 coexpression:651
Rv2759c vapC42 ribonuclease VapC42 623 624 ctx cooccurence:529
Rv3488 hyp hypothetical protein 615 615 coexpression:615
Rv0603 hyp hypothetical protein 580 580 coexpression:580
Rv1558 hyp hypothetical protein 566 565 ctx neighborhood:563
Rv1557 mmpL6 transmembrane transport protein MmpL6 561 561 ctx neighborhood:556

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 exp badge marks an experimentally-supported partner (measured interaction, experimental/database channel ≥400) as opposed to a purely predicted one — but note that the M. tuberculosis experimental interactome is dominated by a noisy bacterial-two-hybrid screen, so a strong measured link that contradicts the operon/localisation context is likely a false positive. 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 VapB11
  • Pfam (hmmscan --cut_ga): VapB_antitoxin PF09957.16 (E=2e-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_216076.1)
  • Domains: Pfam-A via hmmscan --cut_ga — VapB_antitoxin (PF09957.16)
  • 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 COG5450
  • Curated reference: UniProt P9WLU3 (SwissProt, reviewed; Evidence at protein level)
  • Genome-wide structure: AlphaFold DB model (Jumper et al. 2021, doi:10.1038/s41586-021-03819-2; Varadi et al. 2024, doi:10.1093/nar/gkad1011) searched vs PDB with Foldseek (mean pLDDT 85.1)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 29 functional partner(s); context anchor vapC11
  • Essentiality: genome-wide transposon mutagenesis in H37Rv — DeJesus et al. 2017 (mBio, doi:10.1128/mBio.02133-16, CC BY)
  • Proteomics: integrated mass-spectrometry abundance from PaxDb 5.0 (Huang et al. 2023, doi:10.1016/j.mcpro.2023.100640), taxon 83332 — weighted average of 16 datasets, incl. Schubert et al. 2013 (doi:10.1016/j.chom.2013.04.008) and Albrethsen et al. 2013 (doi:10.1074/mcp.M112.018846)
  • Functional category: TubercuList scheme (Cole et al. 1998, doi:10.1038/31159), via Mycobrowser (Kapopoulou et al. 2011, doi:10.1016/j.tube.2010.09.006)
  • Orthologues: reciprocal best hits (DIAMOND, Buchfink et al. 2021, doi:10.1038/s41592-021-01101-x) against Mycobrowser release 5 reference proteomes
  • Experimental structures: PDBe/SIFTS UniProt→PDB mapping (Dana et al. 2019, doi:10.1093/nar/gky1114)
  • Genomic context / operon: H37Rv annotation; operon predicted by co-directional intergenic distance (Salgado et al. 2000, doi:10.1073/pnas.030539397)
  • Transcriptional regulation: ISB signed TRN — TF ChIP-seq (Minch et al. 2015, doi:10.1038/ncomms6829) + TF overexpression (Rustad et al. 2014, doi:10.1186/gb-2014-15-11-502)
  • Physico-chemical properties: ExPASy ProtParam method via Biopython (Gasteiger et al. 2005), computed from the MTBC0 sequence
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv1560|vapB11
MYRWCMSRTNIDIDDELAAEVMRRFGLTTKRAAVDLALRRLVGSPLSREFLLGLEGVGWEGDLDDLRSDRPD