vapB6 Family assigned · medium auto-curated
H37Rv Rv0657c · MTBC0 mtbc0_000695 ·
51 aa · 757548–757703 (-) ·
RefSeq NP_215171.1
Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | antitoxin VapB6 |
|---|---|
| MTBC0 PGAP re-annotation | type II toxin-antitoxin system VapB family antitoxin |
| Revised (this work) | Type II toxin-antitoxin system VapB family antitoxin. Pfam: VapB_antitoxin (PF09957.16). |
Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.
Curated reference (UniProt)
| UniProt |
P9WJ57
SwissProt · reviewed
· Predicted
|
|---|---|
| UniProt name | Putative antitoxin VapB6 |
| Curated function | Antitoxin component of a possible type II toxin-antitoxin (TA) system. The cognate toxin is VapC6. |
UniProt still lists this protein as Putative antitoxin VapB6; the revised annotation above is ahead of the current UniProt record.
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
K Transcription
|
|---|---|
| eggNOG description | Bacterial antitoxin of type II TA system, VapB |
| Orthologous group | COG5450 |
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, 2 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)
| Pfam | Accession | i-Evalue | Residues | Description |
|---|---|---|---|---|
VapB_antitoxin | PF09957.16 | 1.7e-17 | 3–45 | Bacterial antitoxin of type II TA system, VapB |
Functional interaction network (STRING v12, guilt-by-association)
Closest characterised functional partner: vapC6 (ribonuclease VapC6), medium confidence from genomic context alone (score 680 excluding text-mining).
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv0656c vapC6 |
ribonuclease VapC6 | 680 | 680 ctx | neighborhood:599 |
Rv0658c |
integral membrane protein | 621 | 621 ctx | neighborhood:615 |
Rv0598c vapC27 |
ribonuclease VapC27 | 435 | 46 | textmining:433 |
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 VapB6
- MTBC0 PGAP product: type II toxin-antitoxin system VapB family antitoxin
- Pfam (hmmscan --cut_ga): VapB_antitoxin PF09957.16 (E=2e-17)
- (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_215171.1)
- 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 P9WJ57 (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 —
3 functional partner(s); context anchor
vapC6 - Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>mtbc0_000695|Rv0657c|vapB6 MSVTQIDLDDEALADVMRIAAVHTKKEAVNLAMRDYVERFRRIEALARSRE