Rv2264c Family assigned · medium auto-curated

H37Rv Rv2264c · MTBC0 mtbc0_002406 · 592 aa · 2562677–2564455 MTBC0 (-) · RefSeq NP_216780.1

Genomic neighbourhood (genome browser)

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Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)hypothetical protein
MTBC0 PGAP re-annotationHsp70 family protein
Revised (this work)Hsp70 family protein. Pfam: HSP70 (PF00012.27).
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) 1 publication

Found under: H37Rv (1).

1 TB publication mentions this gene. 1 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
Computational identification of significant immunogenic epitopes of the putative outer membrane proteins from Mycobacterium tuberculosis. doi:10.1186/s43141-021-00148-9 2021

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.

Intrinsic disorder (sequence + structure) partially disordered

Predicted disorder40% of residues (metapredict) · mean AlphaFold pLDDT 73.2
Disordered regions2 IDR(s), longest 234 aa [0-13, 358-592]

carries a substantial disordered region (247/592 residues); disorder is a property, not a function

A property (biophysics), not a function. No LLPS/condensate claim is made from disorder alone. Verdict unchanged. Source: metapredict v3 (Emenecker/Holehouse) per-residue disorder + AlphaFold mean pLDDT (annotation_mtbc P16.13).

Genomic-neighbour overlap (structural caveat) antiparallel · 1 % of gene

NeighbourRv2263 (Rv2263, + strand)
Overlap23 bp, 1 % of this gene's length

antiparallel overlap: this gene may inherit essentiality/conservation signal from its neighbour through shared TA sites or promoter constraint, without any protein of its own being produced (cf. Rv2438A/nadE) Signals attributed to this gene (Tn-seq essentiality via shared TA sites, conservation via promoter constraint) should be cross-checked against the neighbour before being read as its own. P20.1, derived from GFF3 gene coordinates, 2026-08-03.

CRISPRi vulnerability

Vulnerability index 0.70 (95% CI -3.47 to 6.25). 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 classes this locus among conserved hypotheticals; the atlas now assigns a functional handle (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 Mb2287c · 100.0% identity
M. marinum MMAR_3358 · 66.4% identity
M. smegmatis MSMEG_4349 · 48.6% identity
M. abscessus MAB_4291 · 40.6% 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 O53538 TrEMBL · unreviewed · Evidence at protein level
UniProt nameConserved hypothetical proline rich protein

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category O Post-translational modification, protein turnover, chaperones
eggNOG descriptionMolecular chaperone
Orthologous groupCOG0443

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 0.394 · purifying
Polymorphic sites (≥ 0.1% of strains) 6 synonymous, 6 missense, 0 nonsense, 8 frameshift
Disruption 8 distinct premature-stop/frameshift site(s); most common in 23.96% of strains (34798) · convergent

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) · 1 consensus substitution(s)
low power (1 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 60.9% · 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
detected in 3/13 non-Mycobacterium reference genomes (down to Corynebacteriales) · mean identity 34.2%
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) 32 in the ORF — 0 in the essential state, 0 growth-defect, 32 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 91.375. 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 abundance7.81 ppm · rank 2773/3519 (21.2th 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.

Predicted localisation (DeepTMHMM + lipobox)

Predictionpredicted membrane protein (1 TM helix)
DeepTMHMM classTM
TM helices (DeepTMHMM)1

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)

Length592 aa
Molecular weight59.8 kDa
Theoretical pI5.04
GRAVY0.021 (hydrophobic)
Aliphatic index87.2
Aromaticity0.037
Instability index48.9 (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
HSP70PF00012.27 1.6e-17150–364 Hsp70 protein

Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 73.2

PDB hitprobTM-scoreE-valueDescription
2v7y-assembly1_A 1.00 0.74 1.3e-19 sig 2v7y-assembly1_A Crystal structure of the molecular chaperone DnaK from Geobacillus kaustophilus HTA426 in post-ATP hydrolysis state
7rax-assembly1_A 1.00 0.69 4.9e-20 sig 7rax-assembly1_A ATP-binding state of the nucleotide-binding domain of Hsp70 DnaK mutant T199A
4b9q-assembly2_B 1.00 0.66 7.2e-20 sig 4b9q-assembly2_B Open conformation of ATP-bound Hsp70 homolog DnaK
7p31-assembly2_B 1.00 0.73 2.6e-18 sig 7p31-assembly2_B Plasmodium falciparum Hsp70-x chaperone nucleotide binding domain in complex with NCL-00023818
7fgm-assembly1_A 1.00 0.71 1.4e-18 sig 7fgm-assembly1_A The complex crystals structure of the FAF1 UBL1_L-Hsp70 NBD with ADP and phosphate

Foldseek search of the AlphaFold DB model (mean pLDDT 73.2, 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)Rv2263 (+ strand, -23 bp gap)
Downstream (3' on genome)Rv2265 (+ strand, 349 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: iniA (isoniazid inductible protein IniA), high confidence from genomic context alone (score 786 excluding text-mining). This association is the citable seed of a function hypothesis for this hypothetical protein.

PartnerProductScoreNo text-miningChannels (≥400)
Rv2299c htpG exp chaperone protein HtpG 977 969 coexpression:668 experimental:772 database:622
Rv0351 grpE exp stress response protein GrpE 961 947 coexpression:703 experimental:773
Rv2373c dnaJ2 exp chaperone protein DnaJ 942 934 coexpression:630 experimental:476 database:601
Rv0352 dnaJ1 exp chaperone protein DnaJ 939 929 coexpression:628 experimental:476 database:601
Rv3417c groEL1 exp chaperonin GroEL 853 829 coexpression:629 experimental:410
Rv0440 groEL2 exp molecular chaperone GroEL 850 826 coexpression:629 experimental:410
Rv0384c clpB exp chaperone protein ClpB 833 809 coexpression:616 experimental:508
Rv2667 clpC2 exp ATP-dependent protease ATP-binding subunit ClpC 833 809 coexpression:615 experimental:508
Rv3596c clpC1 exp ATP-dependent protease ATP-binding subunit ClpC 832 808 coexpression:614 experimental:508
Rv0342 iniA exp isoniazid inductible protein IniA 798 786 ctx cooccurence:587 database:411
Rv3529c hyp exp hypothetical protein 783 772 experimental:455 database:567
Rv2267c stf3 hyp exp hypothetical protein 782 770 experimental:455 database:567
Rv1691 hyp exp hypothetical protein 781 769 experimental:455 database:567
Rv0708 rplP exp 50S ribosomal protein L16 780 760 experimental:749
Rv3418c groES chaperonin GroES 824 759 coexpression:671

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: Hsp70 family protein
  • Pfam (hmmscan --cut_ga): HSP70 PF00012.27 (E=2e-17)
  • (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_216780.1)
  • Domains: Pfam-A via hmmscan --cut_ga — HSP70 (PF00012.27)
  • 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 COG0443
  • Curated reference: UniProt O53538 (TrEMBL, unreviewed; 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 73.2)
  • Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 175 functional partner(s); context anchor iniA
  • 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_002406|Rv2264c|
MATGARPALGLSIGVTNLAAVAADHSITRKPVLTLYRQRPPEVGVPSENPRLDEPGLVITDFVDRVGDSVGIVAADGSVYRSEALVADALLALAYTATGGRALPGSVTVTYPAHWGPAAVAALDSALRRASEWSHGTSSTAQPLSLLPDAAAALYAIRADPGIPARGIVAVCDFGGSGTGITLVDAADEYRPVAATVRHQAFSGDLIDQSLLSYVMSELPGTGAFDPAGTSAIGSLTKLRIECRKAKERLSSSTVTTLTDALGGDIRLTRNELEDTIRDSLDSVGRALEQTLARSGIRTAELVAIVSVGGGANIPAVTTTLSGRFCVPVVRTPRPQLTAAFGGALWAARRPGDTSATVLTAVTSATATAPADAPASVLQPALAWSEADEDSHIGPAPGYTAARPSLSFDHDAHAEPEPKSPPIPWYRLPAVIITGTTVAVLLVGAAVAIGLSTGDQPTAPGTPQRPGVTTTAAPPPSPAPASDGPTTEPAPPVQAPATGGPAPPLQQPLPPPPTTTNTQPAVTTDVITPAPTTPASAPPATTQPPATTQPPATTSPSPPPIPPIPPIPEIPQLPPGIPQVPGIGQFSAISGS