Rv1372 Family assigned · medium auto-curated

H37Rv Rv1372 · MTBC0 - · 393 aa · 1544825–1546006 H37Rv (+) · RefSeq YP_177803.1

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)alpha-pyrone synthesis polyketide synthase-like protein
MTBC0 PGAP re-annotation
Revised (this work)Alpha-pyrone synthesis polyketide synthase-like protein. Pfam: Chal_sti_synt_N (PF00195.26), FAE1_CUT1_RppA (PF08392.19), ACP_syn_III (PF08545.17), Chal_sti_synt_C (PF02797.22), ACP_syn_III_C (PF08541.17).
Functional category (TubercuList)conserved hypotheticals

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).

In the literature (TB corpus sweep) 1 publication

1 TB publication mentions this gene. 1 publication(s) discuss this gene (0 in a M. tuberculosis context, 1 in other mycobacteria — M. marinum (1)).

PublicationDate
Functional flexibility of a type III polyketide synthase in Mycobacterium marinum. doi:10.1016/j.isci.2025.113129 2025

This layer CITES the literature and adds context; it does not change the verdict or the function stated elsewhere in this fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole): H37Rv locus tag + GENE NAME + ortholog identifiers (Mb…, MMAR_…, MSMEG_…, ML…, MAB_…), under a mycobacterial context filter; hits verified against the abstract text. Species-context counts distinguish M. tuberculosis literature from literature on other mycobacteria. phase76/phase77, 2026-07-13.

Genomic-neighbour overlap (structural caveat) co-directional · 0 % of gene

NeighbourRv1371 (Rv1371, + strand)
Overlap4 bp, 0 % of this gene's length

co-directional overlap: ordinary (e.g. shared stop/start codons in an operon), not the Rv2438A-type artefact P20.1, derived from GFF3 gene coordinates, 2026-08-03.

CRISPRi vulnerability

Vulnerability index 1.06 (95% CI -0.71 to 3.61). A more negative index = more vulnerable to knockdown (better drug-target quality); indicative threshold VI ≤ -6 = highly vulnerable.

Quantitative CRISPRi knockdown, graded (finer than binary Tn-seq essentiality). Source: CRISPRi vulnerability index (Bosch 2021, pebble.rockefeller.edu).

Legacy record & comparison (Mycobrowser) ahead of Mycobrowser

Mycobrowser functionFunction unknown

Mycobrowser classes this locus among conserved hypotheticals; the atlas now assigns a functional handle (curated function (UniProt), EC number, COG category). Mycobrowser is no longer maintained, so its EC numbers predate recent nomenclature revisions (e.g. the 2018 EC 7 "translocase" class) — most EC differences are re-numberings of the same enzyme, not conflicts.

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb1406 · 100.0% identity
M. marinum MMAR_2190 · 79.9% identity
M. orygis RJtmp_001452 · 100.0% identity

Reciprocal-best-hit orthologues (DIAMOND) against the Mycobrowser reference proteomes. A missing species is informative: e.g. a gene absent from M. leprae was likely lost in its reductive genome evolution. Locus tags link to Mycobrowser.

Curated reference (UniProt)

UniProt P9WPF1 SwissProt · reviewed · Evidence at protein level
UniProt nameAlpha-pyrone synthesis polyketide synthase-like Pks18
EC (curated) EC 2.3.1.-
Curated functionInvolved in the biosynthesis of tri- and tetraketide alpha-pyrones. Pks18 catalyzes the extension of medium- and long-chain aliphatic acyl-CoA substrates by using malonyl-CoA as an extender molecule to synthesize polyketide products.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category Q Secondary metabolites biosynthesis, transport and catabolism
Preferred namepks18
eggNOG descriptionChalcone and stilbene synthases, C-terminal domain
Orthologous groupCOG3424
KEGG orthology K16167, K16233
Gene Ontology (22) GO:0006725, GO:0008150, GO:0008152, GO:0009058, GO:0009698, GO:0009699, GO:0009714, GO:0009715, GO:0009987, GO:0019438, GO:0019748, GO:0042180 +10 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 1.463 · diversifying/relaxed
Polymorphic sites (≥ 0.1% of strains) 3 synonymous, 13 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.

Outgroup conservation (beyond the MTBC) Corynebacteriales

M. canettii dN/dS (deep-divergence selection) inf (low power) · 2 consensus substitution(s)
low power (2 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 21/53 (40%) · mean identity 73.2% · 4/4 closest MTBAP relatives
present in a subset of the genus (21/53 NTM; in 4 of the 4 closest MTBAP relatives) — partial/intermediate conservation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria
detected in 2/13 non-Mycobacterium reference genomes (down to Corynebacteriales) · mean identity 64.4%
detected across the order Corynebacteriales (Corynebacterium/Nocardia/Rhodococcus/…) but not in more distant Actinomycetia — a Corynebacteriales-level gene

Two orthogonal outgroup signals. M. canettii (the immediate outgroup) gives a deep-divergence dN/dS (a low value confirms a constrained, real gene; shown as confident only at ≥8 substitutions, else flagged low-power). Genus-wide presence/absence (tblastn vs assembled non-MTBC genomes) places the gene on the ancient-core ↔ MTBC-specific axis: a gene absent even from the closest MTBAP relatives is a candidate MTBC-specific innovation (possible host-adaptation factor, to confirm by synteny). The phylostratum extends that axis outside the genus (tblastn vs 13 reference genomes spanning Mycobacteriaceae → Corynebacteriales → Actinomycetia → outside the phylum): it is the deepest clade in which a homolog is still detected, i.e. a proxy for gene age. Read it with the null model in mind: a shallow (young) stratum can also reflect homology-detection failure for short or fast-evolving ORFs, so it is a descriptive axis, not a proof of novelty.

Essentiality (transposon mutagenesis)

DeJesus 2017 callNE · non-essential
What the call meansnon-essential
TA sites (Himar1) 18 in the ORF — 0 in the essential state, 0 growth-defect, 18 non-essential, 0 growth-advantage. Saturation 0.833, mean read count 44.7333333333. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.

Genome-wide Himar1 transposon essentiality in H37Rv (DeJesus 2017). An essential call (ES/ESD/GD) is strong, independent evidence that a "hypothetical" locus encodes a functional, selectively required gene — orthogonal to intra-species conservation.

Proteomics (mass spectrometry) not detected

Not detected in the mass-spectrometry datasets integrated by PaxDb. This is not evidence of absence: low-abundance, condition-specific, or MS-refractory proteins (e.g. small, highly hydrophobic, or repetitive PE/PPE families with few tryptic peptides) are systematically under-sampled.

Physico-chemical properties (computed, ProtParam)

Length393 aa
Molecular weight42.0 kDa
Theoretical pI5.58
GRAVY0.26 (hydrophobic)
Aliphatic index105.4
Aromaticity0.059
Instability index40.0 (unstable)

Computed from the ancestral MTBC0 sequence with the ExPASy ProtParam method (Biopython). Descriptive biophysical context: a positive GRAVY flags a hydrophobic (often membrane) protein, a high instability index (>40) predicts a short in-vitro half-life, an extreme pI hints at compartment or binding partner.

Domains (Pfam, hmmscan --cut_ga)

PfamAccessioni-EvalueResiduesDescription
Chal_sti_synt_NPF00195.26 1.7e-2333–235 Chalcone and stilbene synthases, N-terminal domain
FAE1_CUT1_RppAPF08392.19 1.2e-10131–239 FAE1/Type III polyketide synthase-like protein
ACP_syn_IIIPF08545.17 9.9e-09174–238 3-Oxoacyl-[acyl-carrier-protein (ACP)] synthase III
Chal_sti_synt_CPF02797.22 3.4e-21251–389 Chalcone and stilbene synthases, C-terminal domain
ACP_syn_III_CPF08541.17 3.7e-10299–389 3-Oxoacyl-[acyl-carrier-protein (ACP)] synthase III C terminal

Experimental structures (Protein Data Bank) 2 solved

PDBMethodResolutionCoverage
1ted X-ray diffraction 2.25 Å 100%
1tee X-ray diffraction 2.9 Å 100%

Experimentally solved structures mapped from the UniProt accession via PDBe/SIFTS (2 total; up to 8 shown, ranked by sequence coverage then resolution). An experimental structure is direct proof of the folded product and the strongest structural evidence — superseding the predicted ESMFold/AlphaFold models below for any covered region.

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 92.8

PDB hitprobTM-scoreE-valueDescription
1ted-assembly2_D 1.00 0.99 1.9e-71 sig 1ted-assembly2_D Crystal structure of a type III polyketide synthase PKS18 from Mycobacterium tuberculosis
1tee-assembly1_A 1.00 0.98 9.2e-72 sig 1tee-assembly1_A Crystal structure of C205F mutant of PKS18 from Mycobacterium tuberculosis
7d41-assembly1_B 1.00 0.98 1.8e-65 sig 7d41-assembly1_B Crystal structure of type III polyketide synthase from Mycobacterium marinum - P 21 21 21 Space group
7cb3-assembly1_B 1.00 0.99 3.5e-64 sig 7cb3-assembly1_B Crystal structure of type III polyketide synthase from Mycobacterium marinum
4b0n-assembly1_B 1.00 0.88 2.6e-41 sig 4b0n-assembly1_B Crystal structure of PKS-I from the brown algae Ectocarpus siliculosus

Foldseek search of the AlphaFold DB model (mean pLDDT 92.8, gated at 70) against the PDB — a genome-wide extension of the ESMFold dark-gene search that also covers proteins beyond the single-sequence length limit. Confident structural neighbours (E < 0.01) shown.

Genomic context (neighbours & predicted operon) operon of 3

Upstream (5' on genome)Rv1371 (+ strand, -4 bp gap)
Downstream (3' on genome)Rv1373 (+ strand, 5 bp gap)
Predicted operon Rv1371 · Rv1372 · Rv1373

Neighbours from the H37Rv annotation (+ strand). The operon is predicted by co-directional intergenic distance (same strand, gaps ≤50 bp) — a transcription-unit hypothesis, not a mapped TSS. For a "hypothetical", co-transcription with a characterised operon is a concrete functional lead (complements the STRING neighborhood channel below).

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

Explore full network →

Node colour = verdict, dashed = hypothetical; edge colour = evidence (green experimental, orange genomic-context, grey co-expression), width ∝ score. Click a partner to open its page; "Explore full network" to walk the graph.

Closest characterised functional partner: Rv1371 (membrane protein), high confidence from genomic context alone (score 948 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv1371 membrane protein 978 948 ctx neighborhood:882 cooccurence:448 textmining:601
Rv1139c hyp hypothetical protein 875 832 ctx cooccurence:702 coexpression:400
Rv0261c narK3 nitrate/nitrite transporter 810 810 coexpression:810
Rv1373 glycolipid sulfotransferase 819 806 ctx neighborhood:801
Rv0667 rpoB exp DNA-directed RNA polymerase subunit beta 802 773 experimental:406 database:628
Rv1390 rpoZ exp DNA-directed RNA polymerase subunit omega 771 771 experimental:406 database:629
Rv3457c rpoA exp DNA-directed RNA polymerase subunit alpha 759 759 database:626
Rv1305 atpE exp ATP synthase subunit C 764 754 database:610
Rv0259c hyp hypothetical protein 732 732 coexpression:732
Rv1138c oxidoreductase 753 654 ctx cooccurence:613
Rv2267c stf3 hyp exp hypothetical protein 661 648 database:593
Rv3529c hyp exp hypothetical protein 659 646 database:593
Rv1691 hyp exp hypothetical protein 657 644 database:593
Rv2101 helZ exp helicase HelZ 625 608 database:480
Rv1369c Probable transposase; Rv1369c, (MTCY02B12.03c), len: 328 aa. Probable transposase subunit for IS6110. Identical to many other M. tuberculosi 545 544 ctx neighborhood:543

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 exp badge marks an experimentally-supported partner (measured interaction, experimental/database channel ≥400) as opposed to a purely predicted one — but note that the M. tuberculosis experimental interactome is dominated by a noisy bacterial-two-hybrid screen, so a strong measured link that contradicts the operon/localisation context is likely a false positive. 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): alpha-pyrone synthesis polyketide synthase-like protein
  • Pfam (hmmscan --cut_ga): Chal_sti_synt_N PF00195.26 (E=2e-23), FAE1_CUT1_RppA PF08392.19 (E=1e-10), ACP_syn_III PF08545.17 (E=1e-08), Chal_sti_synt_C PF02797.22 (E=3e-21), ACP_syn_III_C PF08541.17 (E=4e-10)
  • (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_177803.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Chal_sti_synt_N (PF00195.26), FAE1_CUT1_RppA (PF08392.19), ACP_syn_III (PF08545.17), Chal_sti_synt_C (PF02797.22), ACP_syn_III_C (PF08541.17)
  • 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 COG3424
  • Curated reference: UniProt P9WPF1 (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)
  • Genome-wide structure: AlphaFold DB model (Jumper et al. 2021, doi:10.1038/s41586-021-03819-2; Varadi et al. 2024, doi:10.1093/nar/gkad1011) searched vs PDB with Foldseek (mean pLDDT 92.8)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 53 functional partner(s); context anchor Rv1371
  • Essentiality: genome-wide transposon mutagenesis in H37Rv — DeJesus et al. 2017 (mBio, doi:10.1128/mBio.02133-16, CC BY)
  • Functional category: TubercuList scheme (Cole et al. 1998, doi:10.1038/31159), via Mycobrowser (Kapopoulou et al. 2011, doi:10.1016/j.tube.2010.09.006)
  • Orthologues: reciprocal best hits (DIAMOND, Buchfink et al. 2021, doi:10.1038/s41592-021-01101-x) against Mycobrowser release 5 reference proteomes
  • Experimental structures: PDBe/SIFTS UniProt→PDB mapping (Dana et al. 2019, doi:10.1093/nar/gky1114)
  • Genomic context / operon: H37Rv annotation; operon predicted by co-directional intergenic distance (Salgado et al. 2000, doi:10.1073/pnas.030539397)
  • Physico-chemical properties: ExPASy ProtParam method via Biopython (Gasteiger et al. 2005), computed from the MTBC0 sequence
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv1372|
MNVSAESGAPRRAGQRHEVGLAQLPPAPPTTVAVIEGLATGTPRRVVNQSDAADRVAELFLDPGQRERIPRVYQKSRITTRRMAVDPLDAKFDVFRREPATIRDRMHLFYEHAVPLAVDVSKRALAGLPYRAAEIGLLVLATSTGFIAPGVDVAIVKELGLSPSISRVVVNFMGCAAAMNALGTATNYVRAHPAMKALVVCIELCSVNAVFADDINDVVIHSLFGDGCAALVIGASQVQEKLEPGKVVVRSSFSQLLDNTEDGIVLGVNHNGITCELSENLPGYIFSGVAPVVTEMLWDNGLQISDIDLWAIHPGGPKIIEQSVRSLGISAELAAQSWDVLARFGNMLSVSLIFVLETMVQQAESAKAISTGVAFAFGPGVTVEGMLFDIIRR