pptT Resolved · high auto-curated
H37Rv Rv2794c · MTBC0 mtbc0_002973 ·
227 aa · 3125672–3126355 (-) ·
RefSeq NP_217310.1
Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | 4'-phosphopantetheinyl transferase |
|---|---|
| MTBC0 PGAP re-annotation | 4'-phosphopantetheinyl transferase |
| Revised (this work) | 4'-phosphopantetheinyl transferase. Pfam: 4PPT_N (PF17837.7), ACPS (PF01648.26). |
Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.
Curated reference (UniProt)
| UniProt |
O33336
SwissProt · reviewed
· Evidence at protein level
|
|---|---|
| UniProt name | 4'-phosphopantetheinyl transferase PptT |
| EC (curated) |
EC 2.7.8.7
|
| Curated function | Transfers the 4'-phosphopantetheine moiety from coenzyme A to a Ser of acyl-carrier-protein. Involved in post-translational modification of various type-I polyketide synthases required for the formation of both mycolic acids and lipid virulence factors. Acts on Pks13, Mas, PpsA, PpsB, PpsC and PpsD. Also acts on AcpM, the meromycolate extension acyl carrier protein. In addition, is involved in the activation of the acyl carrier protein MbtL and the nonribosomal peptides synthases MbtB and MbtE, which are involved in the biosynthesis of the siderophore mycobactin..; FUNCTION: Required for the r. |
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
Q Secondary metabolites biosynthesis, transport and catabolism
|
|---|---|
| Preferred name | pptA |
| eggNOG description | Belongs to the P-Pant transferase superfamily |
| Orthologous group | COG2977 |
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 | 0.188 · strong purifying |
|---|---|
| Polymorphic sites (≥ 0.1% of strains) | 15 synonymous, 8 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.
Domains (Pfam, hmmscan --cut_ga)
| Pfam | Accession | i-Evalue | Residues | Description |
|---|---|---|---|---|
4PPT_N | PF17837.7 | 4.2e-26 | 36–102 | 4'-phosphopantetheinyl transferase N-terminal domain |
ACPS | PF01648.26 | 2.4e-12 | 110–186 | 4'-phosphopantetheinyl transferase superfamily |
Functional interaction network (STRING v12, guilt-by-association)
Closest characterised functional partner: truB (tRNA pseudouridine synthase B), high confidence from genomic context alone (score 906 excluding text-mining).
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv2795c hyp |
hypothetical protein | 992 | 946 ctx | neighborhood:882 textmining:870 |
Rv2793c truB |
tRNA pseudouridine synthase B | 906 | 906 ctx | neighborhood:882 |
Rv2383c mbtB |
phenyloxazoline synthase | 953 | 895 ctx | neighborhood:544 coexpression:780 textmining:578 |
Rv2790c ltp1 |
lipid-transfer protein | 721 | 716 ctx | neighborhood:712 |
Rv3800c pks13 |
polyketide synthase | 932 | 713 | coexpression:462 textmining:775 |
Rv2789c fadE21 |
acyl-CoA dehydrogenase FadE21 | 710 | 710 ctx | neighborhood:697 |
Rv2384 mbtA |
2,3-dihydroxybenzoate-AMP ligase | 785 | 708 | coexpression:684 |
Rv2799 |
membrane protein | 692 | 692 ctx | neighborhood:691 |
Rv1888A |
Rv1888A, len: 57 aa. Conserved hypothetical protein. Possibly continuation of Rv1889c, part of large family of Mycobacterium tuberculosis pr | 557 | 557 ctx | cooccurence:556 |
Rv2797c hyp |
hypothetical protein | 547 | 546 ctx | neighborhood:542 |
Rv2798c hyp |
hypothetical protein | 545 | 545 ctx | neighborhood:542 |
Rv2796c lppV |
lipoprotein LppV | 545 | 544 ctx | neighborhood:542 |
Rv2792c |
resolvase | 490 | 490 ctx | neighborhood:474 |
Rv2791c tnpB |
transposase | 490 | 490 ctx | neighborhood:474 |
Rv0101 nrp |
peptide synthetase Nrp | 538 | 482 | coexpression:412 |
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 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: 4'-phosphopantetheinyl transferase
- MTBC0 PGAP product: 4'-phosphopantetheinyl transferase
- Pfam (hmmscan --cut_ga): 4PPT_N PF17837.7 (E=4e-26), ACPS PF01648.26 (E=2e-12)
- (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_217310.1)
- Domains: Pfam-A via hmmscan --cut_ga — 4PPT_N (PF17837.7), ACPS (PF01648.26)
- 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
COG2977 - Curated reference: UniProt O33336 (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)
- Interaction network: STRING v12.0 (Szklarczyk et al. 2023,
doi:10.1093/nar/gkac1000), taxon 83332, CC-BY 4.0 —
55 functional partner(s); context anchor
truB - Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>mtbc0_002973|Rv2794c|pptT MTVGTLVASVLPATVFEDLAYAELYSDPPGLTPLPEEAPLIARSVAKRRNEFITVRHCARIALDQLGVPPAPILKGDKGEPCWPDGVVGSLTHCAGYRGAVVGRRDAVRSVGIDAEPHDVLPNGVLDAISLPAERADMPRTMPAALHWDRILFCAKEATYKAWFPLTKRWLGFEDAHITFETDSTGWTGRFVSRILIDGSTLSGPPLTTLRGRWSVERGLVLTAIVL