aftB Resolved · high auto-curated
H37Rv Rv3805c · MTBC0 - ·
627 aa · 4266953–4268836 (-) ·
RefSeq NP_218322.1
Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | terminal beta-(1->2)-arabinofuranosyltransferase |
|---|---|
| MTBC0 PGAP re-annotation | — |
| Revised (this work) | Terminal beta-(1->2)-arabinofuranosyltransferase. Pfam: AftB_C (PF26371.1). |
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 |
O53582
SwissProt · reviewed
· Evidence at protein level
|
|---|---|
| UniProt name | Terminal beta-(1->2)-arabinofuranosyltransferase |
| EC (curated) |
EC 2.4.2.-
|
| Curated function | Involved in the biosynthesis of the arabinogalactan (AG) region of the mycolylarabinogalactan-peptidoglycan (mAGP) complex, an essential component of the mycobacterial cell wall. Catalyzes the transfer of arabinofuranosyl (Araf) residues from the sugar donor decaprenyl-phospho-arabinose (DPA) to the arabinan domain to form terminal beta-(1->2)-linked Araf residues, which marks the end point for AG arabinan biosynthesis before decoration with mycolic acids. |
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
M Cell wall / membrane / envelope biogenesis
|
|---|---|
| Preferred name | aftB |
| eggNOG description | capsule polysaccharide biosynthetic process |
| Orthologous group | COG1807 |
| KEGG orthology |
K13687
|
| CAZy family |
GT89
|
| Gene Ontology (2) |
GO:0008150, GO:0040007
|
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 | 1.615 · diversifying/relaxed |
|---|---|
| Polymorphic sites (≥ 0.1% of strains) | 2 synonymous, 9 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 |
|---|---|---|---|---|
AftB_C | PF26371.1 | 6.5e-31 | 483–596 | AftB family C-terminal domain |
Functional interaction network (STRING v12, guilt-by-association)
Closest characterised functional partner: ubiA (decaprenyl-phosphate phosphoribosyltransferase), high confidence from genomic context alone (score 968 excluding text-mining).
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv3806c ubiA |
decaprenyl-phosphate phosphoribosyltransferase | 981 | 968 ctx | neighborhood:780 coexpression:801 textmining:464 |
Rv3807c |
decaprenylphosphoryl-5-phosphoribose phosphatase | 972 | 956 ctx | neighborhood:780 coexpression:770 textmining:408 |
Rv2673 aftC |
alpha-(1->3)-arabinofuranosyltransferase | 984 | 882 ctx | cooccurence:771 database:500 textmining:878 |
Rv3804c fbpA |
diacylglycerol acyltransferase/mycolyltransferase Ag85A | 864 | 864 ctx | neighborhood:478 cooccurence:514 database:500 |
Rv3802c |
membrane protein | 852 | 848 ctx | cooccurence:771 |
Rv3808c glfT2 |
galactofuranosyl transferase GlfT | 857 | 832 ctx | neighborhood:756 |
Rv0129c fbpC |
diacylglycerol acyltransferase/mycolyltransferase Ag85C | 819 | 820 ctx | cooccurence:600 database:500 |
Rv3794 embA |
arabinosyltransferase A | 949 | 797 ctx | cooccurence:762 textmining:760 |
Rv3795 embB |
arabinosyltransferase B | 948 | 797 ctx | cooccurence:758 textmining:757 |
Rv1886c fbpB |
diacylglycerol acyltransferase/mycolyltransferase Ag85B | 790 | 790 ctx | cooccurence:541 database:500 |
Rv3793 embC |
arabinosyltransferase C | 968 | 768 ctx | cooccurence:756 textmining:870 |
Rv1476 |
membrane protein | 765 | 765 ctx | cooccurence:764 |
Rv3809c glf |
UDP-galactopyranose mutase | 763 | 763 ctx | neighborhood:756 |
Rv3035 hyp |
hypothetical protein | 764 | 756 ctx | cooccurence:753 |
Rv3668c |
protease | 754 | 755 ctx | cooccurence:754 |
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): terminal beta-(1->2)-arabinofuranosyltransferase
- Pfam (hmmscan --cut_ga): AftB_C PF26371.1 (E=6e-31)
- (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_218322.1)
- Domains: Pfam-A via hmmscan --cut_ga — AftB_C (PF26371.1)
- 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
COG1807 - Curated reference: UniProt O53582 (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 —
115 functional partner(s); context anchor
ubiA - Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>H37Rv|Rv3805c|aftB MVRVSLWLSVTAVAVLFGWGSWQRRWIADDGLIVLRTVRNLLAGNGPVFNQGERVEANTSTAWTYLLYVGGWVGGPMRLEYVALALAMVLSLLGMVLLMLGTGRLYAPSLRGRRAIMLPAGALVYIAVPPARDFATSGLESGLVLAYLGLLWWMMVCWSQPLRARPDSQMFLGALAFVAGCSVLVRPEFALIGGLALIMMLIAARTWRRRVLIVLAGGFLPVAYQIFRMGYYGLLVPSTALAKDAAGDKWSQGMIYVSNFNRPYALWVPLVLSVPLGLLLMTARRRPSFLRPVLAPDYGRVARAVQSPPAVVAFIVGSGVLQALYWIRQGGDFMHGRVLLAPLFCLLAPVGVIPILLPDGKDFSRETGRWLVGALSGLWLGIAGWSLWAANSPGMGDDATRVTYSGIVDERRFYAQATGHAHPLTAADYLDYPRMAAVLTALNNTPEGALLLPSGNYNQWDLVPMIRPSSGTAPGGKPAPKPQHAVFFTNMGMLGMNVGLDVRVIDQIGLVNPLAAHTERLKHARIGHDKNLFPDWVIADGPWVKWYPGIPGYIDQQWVTQAEAALQCPATRAVLNSVRAPITLHRFLSNVLHSYEFTRYRIDRVPRYELVRCGLDVPDGPGPPPRE