PE18 Family assigned · medium auto-curated

H37Rv Rv1788 · MTBC0 - · 99 aa · 2026477–2026776 (+) · RefSeq YP_177834.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)PE family protein PE18
MTBC0 PGAP re-annotation
Revised (this work)PE family protein PE18. Pfam: PE (PF00934.26).

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 L7N649 TrEMBL · unreviewed · Predicted
UniProt namePE family protein PE18

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category I Lipid transport and metabolism
eggNOG descriptionPE family
Orthologous groupCOG0657

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 0.707 · relaxed/neutral
Polymorphic sites (≥ 0.1% of strains) 1 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)

PfamAccessioni-EvalueResiduesDescription
PEPF00934.26 1.7e-334–94 PE family

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

Closest characterised functional partner: PPE26 (PPE family protein PPE26), high confidence from genomic context alone (score 812 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv1789 PPE26 PPE family protein PPE26 961 812 ctx neighborhood:812 textmining:804
Rv1787 PPE25 PPE family protein PPE25 865 606 ctx neighborhood:606 textmining:671
Rv1790 PPE27 PPE family protein PPE27 750 95 textmining:735
Rv3435c transmembrane protein 436 41 textmining:436
Rv0245 oxidoreductase 434 41 textmining:434
Rv0213c methyltransferase 434 41 textmining:434
Rv2529 hyp hypothetical protein 434 41 textmining:434
Rv3434c transmembrane protein 432 41 textmining:432
Rv2534c efp elongation factor P 430 41 textmining:430
Rv1829 hyp hypothetical protein 410 41 textmining:410

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): PE family protein PE18
  • Pfam (hmmscan --cut_ga): PE PF00934.26 (E=2e-33)
  • (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_177834.1)
  • Domains: Pfam-A via hmmscan --cut_ga — PE (PF00934.26)
  • 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 COG0657
  • Curated reference: UniProt L7N649 (TrEMBL, unreviewed; 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 — 10 functional partner(s); context anchor PPE26
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv1788|PE18
MSFVTTQPEALAAAAGSLQGIGSALNAQNAAAATPTTGVVPAAADEVSALTAAQFAAHAQIYQAVSAQAAAIHEMFVNTLQMSSGSYAATEAANAAAAG