Rv1794 Family assigned · medium auto-curated

H37Rv Rv1794 · MTBC0 mtbc0_001907 · 300 aa · 2049077–2049979 MTBC0 (+) · RefSeq NP_216310.1

Genomic neighbourhood (genome browser)

Open in full genome browser →

This gene (outlined) in its genomic context; arrows are neighbouring genes coloured by verdict. Click any gene to navigate. Pan and zoom in the full browser.

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)hypothetical protein
MTBC0 PGAP re-annotationESX secretion-associated protein EspG
Revised (this work)ESX secretion-associated protein EspG. Pfam: ESX-1_EspG (PF14011.12).
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.

In the literature (TB corpus sweep) 2 publications

Found under: H37Rv (2).

2 TB publications mention this gene. 2 publication(s) mention this gene (title/abstract), verified against the text. The atlas states the function; these are the primary sources that discuss it.

PublicationDate
Insights into the mutations leading to capreomycin resistance in S-adenosyl-L-methionine binding motif in TlyA from Mycobacterium tuberculosis. doi:10.1080/07391102.2021.1969284 2022
Disruption of the ESX-5 system of Mycobacterium tuberculosis causes loss of PPE protein secretion, reduction of cell wall integrity and strong attenuation. doi:10.1111/j.1365-2958.2012.08001.x 2012

This layer CITES the literature, it does not change the verdict or the function. A gene may be heavily studied (as an antigen, a resistance determinant, a drug target) while its molecular function is settled elsewhere in the fiche. This distinguishes a gene that is dark because nobody has looked from one that is dark despite having been studied. Source: PubMed (whole), MULTI-ALIAS sweep: H37Rv locus tag AND every ortholog identifier (M. bovis Mb…, M. marinum MMAR_…, M. smegmatis MSMEG_…, M. leprae ML…, M. abscessus MAB_…), each hit VERIFIED against the abstract text (word-boundary regex). phase73/phase75, 2026-07-13.

Phenotype-driven functional lead (hypothesis) priority 4.0

disruption advantageous in vivo (growth-restraining in the host).

Corroborating evidenceconserved / under constraint intra-MTBC; Tn-seq growth-defect/essential; STRING-coupled to eccD5 (ESX-5 type VII secretion system protein EccD); structural lead available

This locus is a "hypothetical" with a conditional Tn-seq phenotype. The statement above is a working hypothesis for its functional context, synthesised from the phenotype pattern and the corroborating layers on this page (conservation, STRING coupling, operon, regulon, localisation, structure) — a prioritised requalification candidate to validate, not an established function.

CRISPRi vulnerability

Vulnerability index -4.54 (95% CI -5.15 to -3.90). 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)). 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 Mb1822 · 100.0% identity
M. leprae ML1540c · 88.0% identity
M. marinum MMAR_2676 · 96.7% identity
M. orygis RJtmp_001868 · 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 O53943 SwissProt · reviewed · Evidence at protein level
UniProt nameESX-5 secretion-associated protein EspG5
Curated functionSpecific chaperone for cognate PE/PPE proteins. Plays an important role in preventing aggregation of PE/PPE dimers.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category S Function unknown
Preferred nameespG5
eggNOG descriptionEspG family
Orthologous group2ANCJ
Gene Ontology (8) GO:0005575, GO:0005618, GO:0005623, GO:0005886, GO:0016020, GO:0030312, GO:0044464, GO:0071944

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 0.198 · strong purifying
Polymorphic sites (≥ 0.1% of strains) 5 synonymous, 3 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) Mycobacterium

M. canettii dN/dS (deep-divergence selection) 0.0 (low power) · 4 consensus substitution(s)
low power (4 canettii-consensus substitution(s)); present in M. canettii but dN/dS not reliable
Genus-wide presence (~53 non-MTBC Mycobacterium) present in 50/53 (94%) · mean identity 93.8% · 4/4 closest MTBAP relatives
conserved across the genus (present in 50/53 non-MTBC Mycobacterium genomes, incl. distant relatives) — an ancient core gene predating the genus radiation
Phylostratum (deepest detected homolog) MTBC-specific Mycobacterium Mycobacteriaceae Corynebacteriales Actinomycetia Bacteria

present across the genus Mycobacterium (NTM) but not detected in any non-Mycobacterium genome — a Mycobacterium-genus 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) GD — not strictly essential

DeJesus 2017 callGD · growth-defect
What the call meansgrowth-defect: insertions tolerated but fitness reduced; NOT essential
TA sites (Himar1) 22 in the ORF — 0 in the essential state, 22 growth-defect, 0 non-essential, 0 growth-advantage. Saturation 0.500, mean read count 1.18181818182. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction.
Caveat`essential: true` here is the broad union (ES+ESD+GD) kept for backward compatibility; this gene is NOT strictly essential. Read n_sites_* before writing anything about essentiality.

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.

Mutant phenotypes (conditional Tn-seq, MtbTnDB) in-vivo phenotype

Conditionlog2FCqEffect
fitness in mouse infection (in vivo) +6.380.0 disruption advantageous
fitness in mouse infection (in vivo) +6.360.0 disruption advantageous
fitness in mouse infection (in vivo) +6.060.027 disruption advantageous
Mutants exhibiting altered fitness in the absence of gene marP (other) +5.510.0 disruption advantageous
Differential genetic requirements of clinical Mtb strain (ID=663) from Euro-American lineage (compared to H37Rv control) (strain background) +3.900.016 required
fitness in mouse infection (in vivo) +3.170.0 disruption advantageous
fitness in mouse infection (in vivo) +2.580.0095 disruption advantageous

Conditional fitness of transposon-disruption mutants across 7 significant condition(s) (|log2FC|≥1, q≤0.05), from the standardized MtbTnDB compendium. A negative log2FC means the mutant is depleted — the gene contributes to fitness in that condition. An in-vivo defect for a "hypothetical" is strong evidence it matters for infection, even without a known molecular function. Disruption (Tn insertion), not a clean deletion; genetic-interaction screens excluded.

Proteomics (mass spectrometry) detected

MS detectiondetected in 15 of 16 independent MS datasets
Integrated abundance416.0 ppm · rank 488/3519 (86.2th percentile)

Detection by mass spectrometry is direct, experimental evidence that the protein product exists — orthogonal to sequence conservation and to Tn-seq essentiality, and especially decisive for a "hypothetical" locus. Reproducible detection across several independent datasets (PaxDb) makes the existence claim robust; the integrated abundance places the protein in the proteome's dynamic range.

Physico-chemical properties (computed, ProtParam)

Length300 aa
Molecular weight32.4 kDa
Theoretical pI4.86
GRAVY-0.121 (hydrophilic)
Aliphatic index93.0
Aromaticity0.053
Instability index29.6 (stable)

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
ESX-1_EspGPF14011.12 3.0e-3214–282 EspG family

Experimental structures (Protein Data Bank) 2 solved

PDBMethodResolutionCoverage
4kxr X-ray diffraction 2.6 Å 100%
5xfs 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 93.2

PDB hitprobTM-scoreE-valueDescription
6vj5-assembly1_C 1.00 1.00 7.5e-57 sig 6vj5-assembly1_C Structure of PE25-PPE41(A124L) in complex with EspG5 chaperone from the type VII (ESX-5) secretion system
4w4l-assembly1_C 1.00 0.99 4.4e-57 sig 4w4l-assembly1_C Crystal structure of EspG5 in complex with PE25 and PPE41 from the ESX-5 type VII secretion system of M. tuberculosis
4kxr-assembly1_C 1.00 0.99 7.4e-54 sig 4kxr-assembly1_C Structure of the Mycobacterium tuberculosis type VII secretion system chaperone EspG5 in complex with PE25-PPE41 dimer
5xfs-assembly1_C 1.00 0.99 2.3e-53 sig 5xfs-assembly1_C Crystal structure of PE8-PPE15 in complex with EspG5 from M. tuberculosis
4rcl-assembly1_A 1.00 0.83 3.2e-18 sig 4rcl-assembly1_A Structure of EspG3 chaperone from the type VII (ESX-3) secretion system, space group P43212

Foldseek search of the AlphaFold DB model (mean pLDDT 93.2, 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)

Upstream (5' on genome)esxN (+ strand, 87 bp gap)
Downstream (3' on genome)eccD5 (+ strand, 271 bp gap)

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: eccD5 (ESX-5 type VII secretion system protein EccD), high confidence from genomic context alone (score 734 excluding text-mining). This association is the citable seed of a function hypothesis for this hypothetical protein.

PartnerProductScoreNo text-miningChannels (≥400)
Rv1039c PPE15 exp PPE family protein PPE15 999 999 experimental:999
Rv2430c PPE41 exp PPE family protein PPE41 999 999 experimental:999 textmining:880
Rv2431c PE25 exp PE family protein PE25 967 898 experimental:898 textmining:692
Rv1040c PE8 exp PE family protein PE8 898 898 experimental:898
Rv2768c PPE43 exp PPE family protein PPE43 891 892 experimental:891
Rv2770c PPE44 exp PPE family protein PPE44 891 891 experimental:891
Rv1795 eccD5 ESX-5 type VII secretion system protein EccD 886 734 ctx neighborhood:721 textmining:591
Rv1796 mycP5 membrane-anchored mycosin MycP 836 734 ctx neighborhood:721 textmining:411
Rv1797 eccE5 ESX-5 type VII secretion system protein EccE 807 693 ctx neighborhood:683 textmining:400
Rv1793 esxN ESAT-6 like protein EsxN 787 577 ctx neighborhood:567 textmining:519
Rv1798 eccA5 ESX-5 type VII secretion system protein EccA 727 422 ctx neighborhood:415 textmining:547
Rv1196 PPE18 PPE family protein PPE18 463 309
Rv2352c PPE38 PPE family protein PPE38 571 301 textmining:412
Rv3873 PPE68 PPE family protein PPE68 484 298
Rv1787 PPE25 PPE family protein PPE25 640 295 textmining:511

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

  • Legacy H37Rv annotation: hypothetical protein
  • MTBC0 PGAP product: ESX secretion-associated protein EspG
  • Pfam (hmmscan --cut_ga): ESX-1_EspG PF14011.12 (E=3e-32)
  • (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_216310.1)
  • Domains: Pfam-A via hmmscan --cut_ga — ESX-1_EspG (PF14011.12)
  • 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 2ANCJ
  • Curated reference: UniProt O53943 (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 93.2)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 23 functional partner(s); context anchor eccD5
  • Essentiality: genome-wide transposon mutagenesis in H37Rv — DeJesus et al. 2017 (mBio, doi:10.1128/mBio.02133-16, CC BY)
  • Proteomics: integrated mass-spectrometry abundance from PaxDb 5.0 (Huang et al. 2023, doi:10.1016/j.mcpro.2023.100640), taxon 83332 — weighted average of 16 datasets, incl. Schubert et al. 2013 (doi:10.1016/j.chom.2013.04.008) and Albrethsen et al. 2013 (doi:10.1074/mcp.M112.018846)
  • 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)
  • Mutant phenotypes: standardized Tn-seq compendium MtbTnDB (Jinich et al. 2025, doi:10.1111/mmi.15370), aggregating many primary Tn-seq studies across conditions
  • 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

>mtbc0_001907|Rv1794|
MDQQSTRTDITVNVDGFWMLQALLDIRHVAPELRCRPYVSTDSNDWLNEHPGMAVMREQGIVVNDAVNEQVAARMKVLAAPDLEVVALLSRGKLLYGVIDDENQPPGSRDIPDNEFRVVLARRGQHWVSAVRVGNDITVDDVTVSDSASIAALVMDGLESIHHADPAAINAVNVPMEEMLEATKSWQESGFNVFSGGDLRRMGISAATVAALGQALSDPAAEVAVYARQYRDDAKGPSASVLSLKDGSGGRIALYQQARTAGSGEAWLAICPATPQLVQVGVKTVLDTLPYGEWKTHSRV