Rv0588 Family assigned · medium auto-curated

H37Rv Rv0588 · MTBC0 mtbc0_000618 · 295 aa · 689479–690366 MTBC0 (+) · RefSeq NP_215102.1

Genomic neighbourhood (genome browser)

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)hypothetical protein
MTBC0 PGAP re-annotationABC transporter permease
Revised (this work)ABC transporter permease. Pfam: MlaE (PF02405.22).
Functional category (TubercuList)virulence, detoxification, adaptation

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) never studied

No publication in PubMed mentions this gene in its title or abstract — not under its H37Rv locus tag, nor under any of its ortholog identifiers (M. bovis, M. marinum, M. smegmatis, M. leprae, M. abscessus). The atlas annotation rests on sequence/structure evidence, not on a primary study of this gene.

A verified absence of literature is itself information: it flags an annotation with no primary study behind it. 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.

CRISPRi vulnerability

Vulnerability index -0.60 (95% CI -5.62 to 5.96). 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).

Orthologues (reciprocal best hits across mycobacteria)

M. bovis Mb0603 · 100.0% identity
M. orygis RJtmp_000617 · 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 O07790 TrEMBL · unreviewed · Predicted
UniProt nameConserved hypothetical integral membrane protein YrbE2B

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category Q Secondary metabolites biosynthesis, transport and catabolism
Preferred nameyrbE1B
eggNOG descriptionPermease MlaE
Orthologous groupCOG0767
KEGG orthology K02066
KEGG pathways map02010
KEGG modules M00210, M00669, M00670

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 1.139 · relaxed/neutral
Polymorphic sites (≥ 0.1% of strains) 2 synonymous, 6 missense, 0 nonsense, 1 frameshift
Disruption 1 distinct premature-stop/frameshift site(s); most common in 0.48% of strains (699) · clonal

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) Actinomycetia

Genus-wide presence (~53 non-MTBC Mycobacterium) present in 53/53 (100%) · mean identity 77.2% · 4/4 closest MTBAP relatives
conserved across the genus (present in 53/53 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
detected in 6/13 non-Mycobacterium reference genomes (down to Actinomycetia) · mean identity 54.1%
detected across the class Actinomycetia (beyond Corynebacteriales) but not outside the phylum — an Actinobacteria-level ancient 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) 16 in the ORF — 0 in the essential state, 0 growth-defect, 16 non-essential, 0 growth-advantage. Saturation 0.938, mean read count 50.8. 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) detected

MS detectiondetected in 10 of 16 independent MS datasets
Integrated abundance9.02 ppm · rank 2725/3519 (22.6th 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.

Predicted localisation (DeepTMHMM + lipobox)

Predictionpredicted membrane protein (5 TM helixes)
DeepTMHMM classTM
TM helices (DeepTMHMM)5

Transmembrane topology and signal peptide from DeepTMHMM (deep-learning reference predictor); lipoproteins from a (myco)bacterial lipobox motif. A sequence-based prediction of subcellular context.

Physico-chemical properties (computed, ProtParam)

Length295 aa
Molecular weight31.0 kDa
Theoretical pI9.55
GRAVY0.679 (hydrophobic)
Aliphatic index110.4
Aromaticity0.092
Instability index27.7 (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
MlaEPF02405.22 2.5e-5476–279 Permease MlaE

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 87.7

PDB hitprobTM-scoreE-valueDescription
8fef-assembly1_J 1.00 0.97 1.4e-23 sig 8fef-assembly1_J Structure of Mce1 transporter from Mycobacterium smegmatis (Map0)
7ch9-assembly1_G 1.00 0.79 9.3e-09 sig 7ch9-assembly1_G Cryo-EM structure of P.aeruginosa MlaFEBD
7d06-assembly1_A 1.00 0.89 6.6e-08 sig 7d06-assembly1_A Cryo EM structure of the nucleotide free Acinetobacter MlaFEDB complex
8fee-assembly1_I 1.00 0.83 1.1e-08 sig 8fee-assembly1_I Structure of Mce1 transporter from Mycobacterium smegmatis in the absence of LucB (Map2)
6z5u-assembly1_A 1.00 0.90 2.0e-07 sig 6z5u-assembly1_A Cryo-EM structure of the A. baumannii MlaBDEF complex bound to APPNHP

Foldseek search of the AlphaFold DB model (mean pLDDT 87.7, 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 4

Upstream (5' on genome)yrbE2A (+ strand, 1 bp gap)
Downstream (3' on genome)mce2A (+ strand, 5 bp gap)
Predicted operon mce2R · yrbE2A · Rv0588 · mce2A

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: mce2A (Mce family protein Mce2A), high confidence from genomic context alone (score 994 excluding text-mining). This association is the citable seed of a function hypothesis for this hypothetical protein.

PartnerProductScoreNo text-miningChannels (≥400)
Rv0589 mce2A Mce family protein Mce2A 998 994 ctx neighborhood:786 cooccurence:761 coexpression:843 textmining:688
Rv0590 mce2B Mce-family protein Mce2B; Rv0590, (MTCY19H5.32c), len: 275 aa. Mce2B; belongs to 24-membered Mycobacterium tuberculosis Mce protein family ( 994 994 ctx neighborhood:791 cooccurence:772 coexpression:832
Rv0587 yrbE2A hyp hypothetical protein 991 989 ctx neighborhood:882 coexpression:806
Rv0655 mkl exp ABC transporter ATP-binding protein 990 987 ctx cooccurence:774 coexpression:456 experimental:505 database:800
Rv0591 mce2C Mce family protein Mce2C 987 983 ctx neighborhood:881 cooccurence:767
Rv0592 mce2D Mce family protein Mce2D 970 970 ctx neighborhood:781 cooccurence:770
Rv0594 mce2F Mce family protein Mce2F 984 969 ctx neighborhood:781 cooccurence:764 textmining:529
Rv0593 lprL Mce family lipoprotein LprL 971 969 ctx neighborhood:781 cooccurence:769
Rv0586 mce2R HTH-type transcriptional regulator Mce2R 958 886 ctx neighborhood:882 textmining:653
Rv0590A Mce-family related protein; Rv0590A, len: 84 aa. Probable continuation of mce2B|Rv0590. Can find no frameshift to account for this. Possible 884 880 ctx neighborhood:791
Rv1967 mce3B Mce family protein Mce3B 881 878 ctx cooccurence:771
Rv0171 mce1C Mce family protein Mce1C 884 875 ctx cooccurence:758
Rv3497c mce4C Mce family protein Mce4C 879 875 ctx cooccurence:772
Rv1971 mce3F Mce family protein Mce3F 901 874 ctx cooccurence:770
Rv0170 mce1B Mce family protein Mce1B 877 873 ctx cooccurence:772

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: ABC transporter permease
  • Pfam (hmmscan --cut_ga): MlaE PF02405.22 (E=3e-54)
  • (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_215102.1)
  • Domains: Pfam-A via hmmscan --cut_ga — MlaE (PF02405.22)
  • 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 COG0767
  • Curated reference: UniProt O07790 (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)
  • 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 87.7)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 42 functional partner(s); context anchor mce2A
  • 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
  • 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
  • Predicted localisation: DeepTMHMM (Hallgren et al. 2022, doi:10.1101/2022.04.08.487609) for transmembrane topology and signal peptide
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000618|Rv0588|
MVESSTASAAAVLRARYPRTAASLDRYGGGTARRLERTGTFARFTRISVVQIGWALRRYRRETLRLVAEIGMGTGAMAVVGGTVAIIGFVTLSGGSLIAIQGFASLGNIGVEAFTGFFAALANTRVAAPIVSGVALAATVGAGATAQLGAMRISEEIDALEVMGIKSISFLVSTRILGGLVVIMPLYALALDMAFTSGQVVTTVFYGQSNGTYEHYFRTFLRPEDVGWSVVEVVIIAVVVMITHCYYGYTASGGPVGVGQAVGRSMRFSLVSVVVVVLLAELALYGVDPNFNLTV