Rv3538 Resolved · high auto-curated

H37Rv Rv3538 · MTBC0 - · 286 aa · 3977062–3977922 (+) · RefSeq YP_177986.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)dehydrogenase
MTBC0 PGAP re-annotation
Revised (this work)Dehydrogenase. Pfam: MFE-2_hydrat-2_N (PF22622.3), MaoC_dehydratas (PF01575.26).

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 Q6MWW2 SwissProt · reviewed · Evidence at protein level
UniProt nameEnoyl-CoA hydratase ChsH3
EC (curated) EC 4.2.1.-
Curated functionDegradation of the cholesterol side chain involves 3 multistep beta-oxidation cycles, this is involved in the second cycle. Hydrates bulky steroid enoyl-CoA esters, has highest activity with 3-OCDO-CoA (3-oxochol-4,22-dien-24-oyl-CoA) making (22S)-HOCO-CoA, followed by octenoyl-CoA, with weaker activity on 3-OCDS-CoA (3-oxocholest-4,24-dien-26-oyl-CoA) and none on 3-OPDC-CoA (3-oxo-pregna-4,17-diene-20- carboxyl-CoA). Hydrates the same substrate as EchA19, but the 2 enzymes make different stereoisomers of the product.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category I Lipid transport and metabolism
Preferred namehsd4B
eggNOG descriptiondehydratase
Orthologous groupCOG2030

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 0.144 · strong purifying
Polymorphic sites (≥ 0.1% of strains) 5 synonymous, 2 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)

PfamAccessioni-EvalueResiduesDescription
MFE-2_hydrat-2_NPF22622.3 5.5e-2018–147 MFE-2 hydratase 2 N-terminal domain
MaoC_dehydratasPF01575.26 4.9e-26163–269 MaoC like domain

Functional interaction network (STRING v12, guilt-by-association)

Closest characterised functional partner: kstD (3-oxosteroid 1-dehydrogenase), high confidence from genomic context alone (score 981 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv3537 kstD 3-oxosteroid 1-dehydrogenase 980 981 ctx neighborhood:882 coexpression:818
Rv3548c short-chain type dehydrogenase/reductase 962 963 ctx fusion:900 cooccurence:478
Rv0148 short-chain type dehydrogenase/reductase 956 956 ctx fusion:900
Rv3502c 3-oxoacyl-ACP reductase 955 956 ctx fusion:900
Rv1350 fabG2 3-oxoacyl-ACP reductase FabG 932 932 ctx fusion:900
Rv0242c fabG4 3-oxoacyl-ACP reductase FabG 931 931 ctx fusion:899
Rv3534c hsaF 4-hydroxy-2-oxovalerate aldolase 920 918 ctx neighborhood:606 coexpression:659 database:436
Rv0769 oxidoreductase 916 916 ctx fusion:878
Rv3573c fadE34 acyl-CoA dehydrogenase FadE34 737 737 ctx cooccurence:488
Rv3535c hsaG acetaldehyde dehydrogenase 690 690 ctx neighborhood:673
Rv3536c hsaE hydratase 694 682 ctx neighborhood:676
Rv3540c ltp2 lipid transfer protein 759 680 ctx cooccurence:481
Rv0687 NAD-dependent oxidoreductase 668 667 ctx fusion:514
Rv2790c ltp1 lipid-transfer protein 673 661 ctx cooccurence:458
Rv3562 fadE31 acyl-CoA dehydrogenase FadE31 793 649 textmining:435

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): dehydrogenase
  • Pfam (hmmscan --cut_ga): MFE-2_hydrat-2_N PF22622.3 (E=5e-20), MaoC_dehydratas PF01575.26 (E=5e-26)
  • (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 YP_177986.1)
  • Domains: Pfam-A via hmmscan --cut_ga — MFE-2_hydrat-2_N (PF22622.3), MaoC_dehydratas (PF01575.26)
  • 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 COG2030
  • Curated reference: UniProt Q6MWW2 (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 — 144 functional partner(s); context anchor kstD
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>H37Rv|Rv3538|
MPIDLDVALGAQLPPVEFSWTSTDVQLYQLGLGAGSDPMNPRELSYLADDTPQVLPTFGNVAATFHLTTPPTVQFPGIDIELSKVLHASERVEVPAPLPPSGSARAVTRFTDIWDKGKAAVICSETTATTPDGLLLWTQKRSIYARGEGGFGGKRGPSGSDVAPERAPDLQVAMPILPQQALLYRLCGDRNPLHSDPEFAAAAGFPRPILHGLCTYGMTCKAIVDALLDSDATAVAGYGARFAGVAYPGETLTVNVWKDGRRLVASVVAPTRDNAVVLSGVELVPA