PPE66 Family assigned · medium auto-curated

H37Rv Rv3738c · MTBC0 - · 315 aa · 4189285–4190232 (-) · RefSeq YP_178009.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)PPE family protein PPE66
MTBC0 PGAP re-annotation
Revised (this work)PPE family protein PPE66. Pfam: PPE (PF00823.26), PPE-PPW (PF18878.6).

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 P9WHX1 SwissProt · reviewed · Inferred from homology
UniProt nameUncharacterized PPE family protein PPE66

UniProt still lists this protein as Uncharacterized PPE family protein PPE66; the revised annotation above is ahead of the current UniProt record.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category N Cell motility
eggNOG descriptionPPE family
Orthologous groupCOG5651

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 1.33 · diversifying/relaxed
Polymorphic sites (≥ 0.1% of strains) 2 synonymous, 7 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
PPEPF00823.26 3.7e-242–73 PPE family
PPE-PPWPF18878.6 4.1e-20259–305 PPE-PPW subfamily C-terminal region

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

Closest characterised functional partner: PPE67 (PPE family protein PPE67), high confidence from genomic context alone (score 787 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv3739c PPE67 PPE family protein PPE67 891 787 ctx neighborhood:627 textmining:510
Rv3517 hyp hypothetical protein 667 62 textmining:660
Rv3426 PPE58 PPE family protein PPE58 444 55 textmining:436
Rv2353c PPE39 PPE family protein PPE39 438 50 textmining:433
Rv0305c PPE6 PPE family protein PPE6 437 47 textmining:434
Rv3017c esxQ ESAT-6 like protein EsxQ 430 46 textmining:428
Rv1519 hyp hypothetical protein 651 44 textmining:650
Rv0354c PPE7 PPE family protein PPE7 435 44 textmining:434

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): PPE family protein PPE66
  • Pfam (hmmscan --cut_ga): PPE PF00823.26 (E=4e-24), PPE-PPW PF18878.6 (E=4e-20)
  • (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_178009.1)
  • Domains: Pfam-A via hmmscan --cut_ga — PPE (PF00823.26), PPE-PPW (PF18878.6)
  • 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 COG5651
  • Curated reference: UniProt P9WHX1 (SwissProt, reviewed; Inferred from homology)
  • 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 — 8 functional partner(s); context anchor PPE67
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv3738c|PPE66
MTTAYASALAAMPTLTELAANHTSHAVLLGTNFFGINTIPIALNEADYARMWIQAATTMSIYEGTSDAALASAPQTTPAPVLFNGGAGVASALPAISAATLDPASIIGIIIEILIQLFLISLEILFAIVAYTIIIVLILPLVIFAYAIVFAVLAIIFGPPLLVIASPFVLTGSVIAVPTSLSTSLSTAVPIGVGQYLADLASADAQAIEVGLKTADVAPVAVRPAAAPPLRESAAVRPEARLVSAVAPAPAGTSASVLASDRGAGVLGFAGTAGKESVGRPAGLTTLAGGEFGGSPSVPMVPASWEQLVGAGEAG