Rv0750 Still unknown · low auto-curated
H37Rv Rv0750 · MTBC0 mtbc0_000797 ·
81 aa ·
846458–846703 MTBC0
(+) ·
RefSeq NP_215264.1
Genomic neighbourhood (genome browser)
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Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | hypothetical protein |
|---|---|
| MTBC0 PGAP re-annotation | hypothetical protein |
| Revised (this work) | Conserved hypothetical protein; DUF domain(s) DUF7956. Function unknown. |
| 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) never studied
No TB publication mentions this locus tag in its title or abstract (sweep of a ~330k-abstract PubMed TB corpus). This gene is genuinely unstudied: its darkness reflects absence of investigation, not failure of investigation.
An antigen status or a virulence phenotype is NOT a molecular function: the verdict stays unchanged. This layer adds the missing context, it does not requalify the gene. 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 of title+abstract: the 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, 2026-07-13.
CRISPRi vulnerability
Vulnerability index 1.00 (95% CI -2.48 to 5.41). 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)
| Mycobrowser function | Function unknown |
|---|
The legacy Mycobrowser record is shown for verification. Mycobrowser is no longer maintained; its EC numbers predate recent nomenclature revisions, so a class change usually reflects re-numbering, not a conflict.
Orthologues (reciprocal best hits across mycobacteria)
| M. bovis |
Mb0772
· 100.0% identity |
|---|---|
| M. orygis |
RJtmp_000794
· 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 |
O53813
TrEMBL · unreviewed
· Predicted
|
|---|---|
| UniProt name | Uncharacterized protein |
UniProt still lists this protein as Uncharacterized protein; the revised annotation above is ahead of the current UniProt record.
Conservation & selection (intra-MTBC, 145 209 strains)
| pN/pS | 0.242 · purifying |
|---|---|
| Polymorphic sites (≥ 0.1% of strains) | 4 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
| Genus-wide presence (~53 non-MTBC Mycobacterium) |
present in 4/53 (8%) · mean identity 76.8%
· 1/4 closest MTBAP relatives present in a subset of the genus (4/53 NTM; in 1 of the 4 closest MTBAP relatives) — partial/intermediate conservation |
|---|---|
| Phylostratum (deepest detected homolog) |
MTBC-specific → Mycobacterium → Mycobacteriaceae → Corynebacteriales → Actinomycetia → Bacteria short ORF (81 aa) a shallow stratum may reflect homology-detection failure, not true youth 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)
| DeJesus 2017 call | NE · non-essential |
|---|---|
| What the call means | non-essential |
| TA sites (Himar1) | 5 in the ORF — 0 in the essential state, 0 growth-defect, 5 non-essential, 0 growth-advantage. Saturation 1.000, mean read count 84. A region of the protein devoid of TA sites is invisible to this assay: nothing can be inferred about it, in either direction. |
| Caveat | Read with some caution: only 5 TA (Himar1) sites in the whole ORF (atlas median 13). The DeJesus 2017 call rests on fewer independent observations than for a longer gene. If this gene overlaps a neighbour (see Genomic-neighbour overlap section below), some of these 5 sites may fall inside the neighbour's ORF rather than its own, leaving even fewer truly informative sites than the raw count suggests. (P20.3) |
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 9 of 16 independent MS datasets |
|---|---|
| Integrated abundance | 21.9 ppm · rank 2286/3519 (35.1th 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)
| Length | 81 aa |
|---|---|
| Molecular weight | 8.7 kDa |
| Theoretical pI | 4.37 |
| GRAVY | -0.048 (hydrophilic) |
| Aliphatic index | 90.4 |
| Aromaticity | 0.074 |
| Instability index | 23.1 (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)
| Pfam | Accession | i-Evalue | Residues | Description |
|---|---|---|---|---|
DUF7956 | PF25845.1 | 6.7e-29 | 1–54 | Domain of unknown function (DUF7956) |
Genomic context (neighbours & predicted operon)
| Upstream (5' on genome) | Rv0749A (- strand, 158 bp gap) |
|---|---|
| Downstream (3' on genome) | mmsB (- strand, 68 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.
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv0749A hyp |
hypothetical protein | 539 | 539 ctx | neighborhood:528 |
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: hypothetical protein
- Pfam (hmmscan --cut_ga): DUF7956 PF25845.1 (E=7e-29)
- (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_215264.1)
- Domains: Pfam-A via hmmscan --cut_ga — DUF7956 (PF25845.1)
- Sequence-level signal: ESM Atlas (EvolutionaryScale × BioHub) — exploratory
- Curated reference: UniProt O53813 (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)
- Model confidence: ESMFold per-residue pLDDT (mean 44.6, very low)
- Interaction network: STRING v12.0 (Szklarczyk et al. 2023, doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 — 1 functional partner(s)
- 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
- Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>mtbc0_000797|Rv0750| MRAIVGDCVIHIMPMGTGVELSKLADLALDIGRSVGCSAYENDFTLPDIPTQWRNQPLGWYTQGLAPYLPGLSDPKDAAEG
Spot an error? Suggest an improvement
Found a mistake, a missing reference, or have a better functional hypothesis for Rv0750? Email the maintainer — the message is pre-filled with this gene's details.