kshB Family assigned · medium auto-curated

H37Rv Rv3571 · MTBC0 mtbc0_003790 · 358 aa · 4036094–4037170 (+) · RefSeq NP_218088.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)3-ketosteroid-9-alpha-hydroxylase reductase subunit
MTBC0 PGAP re-annotation3-ketosteroid-9-alpha-hydroxylase reductase subunit
Revised (this work)3-ketosteroid-9-alpha-hydroxylase reductase subunit. Pfam: FAD_binding_6 (PF00970.31), NAD_binding_1 (PF00175.27), Fer2 (PF00111.33).

Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.

Curated reference (UniProt)

UniProt P9WJ93 SwissProt · reviewed · Evidence at protein level
UniProt name3-ketosteroid-9-alpha-monooxygenase, ferredoxin reductase component
EC (curated) EC 1.14.15.30
Curated functionInvolved in the degradation of cholesterol. Catalyzes the introduction of a 9a-hydroxyl moiety into 1,4-androstadiene-3,17-dione (ADD) to yield the 9alpha-hydroxy-1,4-androstadiene-3,17-dione (9OHADD) intermediate which spontaneously form 3-hydroxy-9,10-seconandrost-1,3,5(10)-triene-9,17-dione (HSA) via the meta-cleavage of ring B with concomitant aromatization of ring A. KSH is also able to use 4-androstene-3,17-dione (AD), 3-oxo-23,24-bisnorcholesta-4-en-22-oate (4-BNC), 3-oxo-23,24-bisnorcholesta-1,4-dien-22-oate (1,4-BNC), 3-oxo-23,24-bisnorcholesta-4-en-22-oyl-coenzyme A thioester (4-BNC-.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category C Energy production and conversion
Preferred namehmp
eggNOG descriptionCOG1018 Flavodoxin reductases (ferredoxin-NADPH reductases) family 1
Orthologous groupCOG1018
EC number EC 1.14.13.142
KEGG orthology K15983
KEGG pathways map00984, map01100, map01120
Gene Ontology (77) GO:0000166, GO:0001666, GO:0003674, GO:0003824, GO:0004497, GO:0005488, GO:0006066, GO:0006629, GO:0006643, GO:0006664, GO:0006706, GO:0006707 +65 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 0.276 · purifying
Polymorphic sites (≥ 0.1% of strains) 5 synonymous, 4 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
FAD_binding_6PF00970.31 6.6e-0847–121 Oxidoreductase FAD-binding domain
NAD_binding_1PF00175.27 2.6e-12132–229 Oxidoreductase NAD-binding domain
Fer2PF00111.33 3.6e-16274–348 2Fe-2S iron-sulfur cluster binding domain

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

Closest characterised functional partner: kshA (3-ketosteroid-9-alpha-monooxygenase oxygenase subunit), high confidence from genomic context alone (score 959 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv3526 kshA 3-ketosteroid-9-alpha-monooxygenase oxygenase subunit 998 959 ctx cooccurence:450 database:900 textmining:964
Rv3537 kstD 3-oxosteroid 1-dehydrogenase 992 936 database:900 textmining:895
Rv3568c hsaC extradiol dioxygenase 977 887 ctx neighborhood:765 cooccurence:484 textmining:811
Rv3570c hsaA flavin-dependent monooxygenase oxygenase subunit HsaA 945 880 ctx neighborhood:772 cooccurence:472 textmining:563
Rv3572 hyp hypothetical protein 857 857 ctx neighborhood:855
Rv1465 nitrogen fixation related protein 868 849 database:621
Rv3025c iscS cysteine desulfurase 854 834 experimental:422 database:621
Rv3569c hsaD 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-diene-4-oate hydrolase 939 831 ctx neighborhood:765 textmining:657
Rv3567c hsaB flavin-dependent monooxygenase reductase subunit HsaB 927 795 ctx neighborhood:758 textmining:662
Rv1175c fadH NADPH dependent 2,4-dienoyl-CoA reductase FadH 837 777 experimental:430 database:568
Rv0886 fprB ferredoxin/ferredoxin--NADP reductase 866 773 experimental:430 database:568 textmining:436
Rv3106 fprA NADPH-ferredoxin reductase FprA 778 752 experimental:430 database:568
Rv3858c gltD glutamate synthase small subunit 777 751 experimental:430 database:568
Rv3153 nuoI NADH-quinone oxidoreductase subunit I 784 750 experimental:700
Rv2940c mas multifunctional mycocerosic acid synthase 808 731 experimental:703

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: 3-ketosteroid-9-alpha-hydroxylase reductase subunit
  • MTBC0 PGAP product: 3-ketosteroid-9-alpha-hydroxylase reductase subunit
  • Pfam (hmmscan --cut_ga): FAD_binding_6 PF00970.31 (E=7e-08), NAD_binding_1 PF00175.27 (E=3e-12), Fer2 PF00111.33 (E=4e-16)
  • (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_218088.1)
  • Domains: Pfam-A via hmmscan --cut_ga — FAD_binding_6 (PF00970.31), NAD_binding_1 (PF00175.27), Fer2 (PF00111.33)
  • 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 COG1018
  • Curated reference: UniProt P9WJ93 (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 — 130 functional partner(s); context anchor kshA
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_003790|Rv3571|kshB
MTEAIGDEPLGDHVLELQIAEVVDETDEARSLVFAVPDGSDDPEIPPRRLRYAPGQFLTLRVPSERTGSVARCYSLCSSPYTDDALAVTVKRTADGYASNWLCDHAQVGMRIHVLAPSGNFVPTTLDADFLLLAAGSGITPIMSICKSALAEGGGQVTLLYANRDDRSVIFGDALRELAAKYPDRLTVLHWLESLQGLPSASALAKLVAPYTDRPVFICGPGPFMQAARDALAALKVPAQQVHIEVFKSLESDPFAAVKVDDSGDEAPATAVVELDGQTHTVSWPRTAKLLDVLLAAGLDAPFSCREGHCGACACTLRAGKVNMGVNDVLEQQDLDEGLILACQSRPESDSVEVTYDE