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-annotation | Hsp70 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.
| Publication | Date |
|---|---|
| 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 disorder | 40% of residues (metapredict) · mean AlphaFold pLDDT 73.2 |
|---|---|
| Disordered regions | 2 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
| Neighbour | Rv2263 (Rv2263, + strand) |
|---|---|
| Overlap | 23 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 name | Conserved hypothetical proline rich protein |
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
O Post-translational modification, protein turnover, chaperones
|
|---|---|
| eggNOG description | Molecular chaperone |
| Orthologous group | COG0443 |
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 call | NE · non-essential |
|---|---|
| What the call means | non-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 detection | detected in 10 of 16 independent MS datasets |
|---|---|
| Integrated abundance | 7.81 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)
| Prediction | predicted membrane protein (1 TM helix) |
|---|---|
| DeepTMHMM class | TM |
| 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)
| Length | 592 aa |
|---|---|
| Molecular weight | 59.8 kDa |
| Theoretical pI | 5.04 |
| GRAVY | 0.021 (hydrophobic) |
| Aliphatic index | 87.2 |
| Aromaticity | 0.037 |
| Instability index | 48.9 (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)
| Pfam | Accession | i-Evalue | Residues | Description |
|---|---|---|---|---|
HSP70 | PF00012.27 | 1.6e-17 | 150–364 | Hsp70 protein |
Structural search (AlphaFold DB model, Foldseek vs PDB — genome-wide) pLDDT 73.2
| PDB hit | prob | TM-score | E-value | Description |
|---|---|---|---|---|
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.
| Partner | Product | Score | No text-mining | Channels (≥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
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