vapB44 Family assigned · low auto-curated

H37Rv Rv3321c · MTBC0 mtbc0_003531 · 80 aa · 3730212–3730454 (-) · RefSeq NP_217838.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)antitoxin VapB44
MTBC0 PGAP re-annotationCopG family transcriptional regulator
Revised (this work)CopG family transcriptional regulator.

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

Curated reference (UniProt)

UniProt P9WJ17 SwissProt · reviewed · Predicted
UniProt namePutative antitoxin VapB44
Curated functionPossibly the antitoxin component of a type II toxin-antitoxin (TA) system. Its cognate toxin is VapC44.

UniProt still lists this protein as Putative antitoxin VapB44; the revised annotation above is ahead of the current UniProt record.

Functional vocabulary (eggNOG-mapper, orthology transfer)

Orthologous group2DSQK
Gene Ontology (15) GO:0008150, GO:0009605, GO:0009607, GO:0043207, GO:0044403, GO:0044419, GO:0050896, GO:0051701, GO:0051704, GO:0051707, GO:0052173, GO:0052200 +3 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.

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)

No Pfam-A domain above the gathering threshold (or not yet scanned).

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

Closest characterised functional partner: vapC44 (ribonuclease VapC44), high confidence from genomic context alone (score 911 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv3320c vapC44 ribonuclease VapC44 911 911 ctx neighborhood:882
Rv3323c moaX MoaD-MoaE fusion protein MoaX 566 567 ctx neighborhood:564
Rv3322c methyltransferase 565 565 ctx neighborhood:564
Rv3324c moaC3 cyclic pyranopterin monophosphate synthase accessory protein 521 522 ctx neighborhood:519
Rv3324A Rv3324A, len: 44 aa. Probable pseudogene moaB3,fragment of pterin-4-alpha-carbinolamine dehydratase,equivalent to C-terminus of MT3426|Q8VJ3 521 521 ctx neighborhood:519
Rv2494 vapC38 ribonuclease VapC38 426 68 textmining:410
Rv2547 vapB19 antitoxin VapB19 807 64 textmining:803
Rv2493 vapB38 antitoxin VapB38 662 55 textmining:658
Rv0301 vapC2 ribonuclease VapC2 527 55 textmining:520
Rv1494 mazE4 antitoxin MazE4 527 53 textmining:522
Rv2601A vapB41 antitoxin VapB41 551 51 textmining:547
Rv0608 vapB28 antitoxin VapB28 626 47 textmining:624
Rv1114 vapC32 ribonuclease VapC32 544 47 textmining:542
Rv2545 vapB18 antitoxin VapB18 676 46 textmining:675
Rv0623 vapB30 antitoxin VapB30 550 46 textmining:548

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 VapB44
  • MTBC0 PGAP product: CopG family transcriptional regulator
  • (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_217838.1)
  • Domains: Pfam-A via hmmscan --cut_ga — none above threshold
  • 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 2DSQK
  • Curated reference: UniProt P9WJ17 (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 — 22 functional partner(s); context anchor vapC44
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_003531|Rv3321c|vapB44
MRTTLSIDDDVLLAVKERARREKRTAGEILSDLARQALTNQNPQPAASQEDAFHGFEPLPHRGGAVSNALIDRLRDEEAV