kasB Resolved · high auto-curated
H37Rv Rv2246 · MTBC0 - ·
438 aa · 2519396–2520712 (+) ·
RefSeq NP_216762.1
Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | 3-oxoacyl-ACP synthase 2 |
|---|---|
| MTBC0 PGAP re-annotation | — |
| Revised (this work) | 3-oxoacyl-ACP synthase 2. Pfam: ketoacyl-synt (PF00109.33), Thiolase_N (PF00108.30), Ketoacyl-synt_C (PF02801.29). |
Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.
Annotated on the H37Rv protein: this gene has no 1:1 ancestral MTBC0 anchor (PE/PPE, paralogue, IS element, or otherwise unanchored CDS).
Curated reference (UniProt)
| UniProt |
P9WQD7
SwissProt · reviewed
· Evidence at protein level
|
|---|---|
| UniProt name | 3-oxoacyl-[acyl-carrier-protein] synthase 2 |
| EC (curated) |
EC 2.3.1.294
|
| Curated function | Part of the mycobacterial fatty acid elongation system FAS-II, which is involved in mycolic acid biosynthesis. Catalyzes the elongation of long chain acyl-ACP substrates by the addition of two carbons from malonyl-ACP to an acyl acceptor. Involved in extension of the mycolate chains to full lengths and produces longer chain multiunsaturated hydrocarbons averaging 54 carbons in length. Essential for resistance to macrophage antimicrobial activity. |
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
I Lipid transport and metabolismQ Secondary metabolites biosynthesis, transport and catabolism
|
|---|---|
| Preferred name | fabF |
| eggNOG description | Belongs to the beta-ketoacyl-ACP synthases family |
| Orthologous group | COG0304 |
| EC number |
EC 2.3.1.179
|
| KEGG orthology |
K09458, K11609
|
| KEGG pathways |
map00061, map00780, map01100, map01212
|
| KEGG modules |
M00083, M00572
|
| Gene Ontology (61) |
GO:0001666, GO:0003674, GO:0003824, GO:0004312, GO:0004315, GO:0005575, GO:0005618, GO:0005623, GO:0005886, GO:0006082, GO:0006629, GO:0006631 +49 more
|
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 | 0.069 · strong purifying |
|---|---|
| Polymorphic sites (≥ 0.1% of strains) | 5 synonymous, 1 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 |
|---|---|---|---|---|
ketoacyl-synt | PF00109.33 | 1.1e-52 | 34–273 | Beta-ketoacyl synthase, N-terminal domain |
Thiolase_N | PF00108.30 | 1.4e-07 | 166–220 | Thiolase, N-terminal domain |
Ketoacyl-synt_C | PF02801.29 | 1.4e-34 | 283–395 | Beta-ketoacyl synthase, C-terminal domain |
Functional interaction network (STRING v12, guilt-by-association)
Closest characterised functional partner: fabD (malonyl CoA-acyl carrier protein transacylase), high confidence from genomic context alone (score 997 excluding text-mining).
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv2243 fabD |
malonyl CoA-acyl carrier protein transacylase | 999 | 997 ctx | neighborhood:758 cooccurence:769 coexpression:941 textmining:930 |
Rv2245 kasA |
3-oxoacyl-ACP synthase 1 | 977 | 977 ctx | neighborhood:836 coexpression:860 |
Rv2247 accD6 |
acetyl-/propionyl-CoA carboxylase subunit beta | 996 | 976 ctx | neighborhood:836 coexpression:860 textmining:841 |
Rv0904c accD3 |
acetyl-CoAcarboxylase carboxyl transferase subunit beta | 983 | 976 | coexpression:961 |
Rv2244 acpM |
meromycolate extension acyl carrier protein | 996 | 956 ctx | neighborhood:836 coexpression:463 experimental:408 textmining:929 |
Rv0533c fabH |
3-oxoacyl-ACP synthase III | 988 | 920 ctx | cooccurence:745 coexpression:678 textmining:860 |
Rv1663 pks17 |
polyketide synthase | 923 | 918 | coexpression:443 experimental:785 |
Rv1527c pks5 |
polyketide synthase | 928 | 900 | coexpression:491 experimental:785 |
Rv2940c mas |
multifunctional mycocerosic acid synthase | 926 | 900 | coexpression:491 experimental:785 |
Rv2933 ppsC |
phthiocerol synthesis polyketide synthase type I PpsC | 927 | 899 | coexpression:486 experimental:785 |
Rv3825c pks2 |
phthioceranic/hydroxyphthioceranic acid synthase | 925 | 899 | coexpression:485 experimental:785 |
Rv2048c pks12 |
polyketide synthase | 925 | 899 | coexpression:488 experimental:785 |
Rv1484 inhA |
NADH-dependent enoyl-[ACP | 982 | 840 ctx | cooccurence:477 coexpression:689 textmining:896 |
Rv3285 accA3 |
bifunctional protein acetyl-/propionyl-CoA carboxylase subunit alpha AccA | 846 | 806 ctx | cooccurence:650 coexpression:450 |
Rv1483 fabG1 |
3-oxoacyl-ACP reductase FabG | 913 | 794 ctx | cooccurence:658 textmining:598 |
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
- Annotation from H37Rv (no MTBC0 1:1 anchor; H37Rv protein used): 3-oxoacyl-ACP synthase 2
- Pfam (hmmscan --cut_ga): ketoacyl-synt PF00109.33 (E=1e-52), Thiolase_N PF00108.30 (E=1e-07), Ketoacyl-synt_C PF02801.29 (E=1e-34)
- (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_216762.1)
- Domains: Pfam-A via hmmscan --cut_ga — ketoacyl-synt (PF00109.33), Thiolase_N (PF00108.30), Ketoacyl-synt_C (PF02801.29)
- 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
COG0304 - Curated reference: UniProt P9WQD7 (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 —
116 functional partner(s); context anchor
fabD - Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>H37Rv|Rv2246|kasB MGVPPLAGASRTDMEGTFARPMTELVTGKAFPYVVVTGIAMTTALATDAETTWKLLLDRQSGIRTLDDPFVEEFDLPVRIGGHLLEEFDHQLTRIELRRMGYLQRMSTVLSRRLWENAGSPEVDTNRLMVSIGTGLGSAEELVFSYDDMRARGMKAVSPLTVQKYMPNGAAAAVGLERHAKAGVMTPVSACASGAEAIARAWQQIVLGEADAAICGGVETRIEAVPIAGFAQMRIVMSTNNDDPAGACRPFDRDRDGFVFGEGGALLLIETEEHAKARGANILARIMGASITSDGFHMVAPDPNGERAGHAITRAIQLAGLAPGDIDHVNAHATGTQVGDLAEGRAINNALGGNRPAVYAPKSALGHSVGAVGAVESILTVLALRDQVIPPTLNLVNLDPEIDLDVVAGEPRPGNYRYAINNSFGFGGHNVAIAFGRY