mftC Resolved · high auto-curated

H37Rv Rv0693 · MTBC0 mtbc0_000734 · 391 aa · 796243–797418 (+) · RefSeq NP_215207.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)mycofactocin radical SAM maturase MftC
MTBC0 PGAP re-annotationmycofactocin radical SAM maturase
Revised (this work)Mycofactocin radical SAM maturase. Pfam: Radical_SAM (PF04055.28), SPASM (PF13186.12).

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

Curated reference (UniProt)

UniProt P9WJ79 SwissProt · reviewed · Evidence at protein level
UniProt nameMycofactocin maturase MftC
EC (curated) EC 1.3.98.7, EC 4.1.99.26
Curated functionRadical S-adenosylmethionine (SAM) enzyme responsible for the first step of the biosynthesis of the enzyme cofactor mycofactocin (MFT). Catalyzes two reactions at the C-terminus of the mycofactocin precursor (the MftA peptide). The first one is the oxidative decarboxylation of the C-terminal L-tyrosine of MftA, forming an unsaturated tyramine moiety. The second reaction is the cross-linking of the tyramine with the penultimate L-valine residue, forming a five-membered lactam ring. Its activity requires the presence of the MftB chaperone.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category C Energy production and conversion
Preferred namepqqE
eggNOG descriptionRadical SAM
Orthologous groupCOG0535
Gene Ontology (6) GO:0005575, GO:0005623, GO:0005886, GO:0016020, GO:0044464, GO:0071944

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 0.226 · purifying
Polymorphic sites (≥ 0.1% of strains) 6 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
Radical_SAMPF04055.28 1.9e-2825–180 Radical SAM superfamily
SPASMPF13186.12 1.5e-06251–313 Iron-sulfur cluster-binding domain

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

Closest characterised functional partner: mftB (mycofactocin system protein MftB), high confidence from genomic context alone (score 1000 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv0692 mftB mycofactocin system protein MftB 999 1000 ctx neighborhood:882 cooccurence:774 coexpression:845 database:900 textmining:907
Rv0694 mftD mycofactocin system heme/flavin oxidoreductase MftD 999 994 ctx neighborhood:882 cooccurence:665 coexpression:860 textmining:875
Rv0695 mftE mycofactocin system creatinine amidohydrolase family protein MftE 995 970 ctx neighborhood:738 cooccurence:758 database:500 textmining:861
Rv0696 mftF mycofactocin biosynthesis glycosyltransferase MftF 993 932 ctx neighborhood:702 cooccurence:770 textmining:907
Rv0691c mftR mycofactocin biosynthesis transcriptional regulator MftR 961 893 ctx neighborhood:602 cooccurence:741 textmining:658
Rv0691A mftA mycofactocin precursor 957 882 ctx neighborhood:882 textmining:655
Rv0697 mftG dehydrogenase 718 706 ctx neighborhood:702
Rv1990A Rv1990A, len: 111 aa. Possible dehydrogenase (fragment), similar to N-terminal part of several dehydrogenases and hypothetical proteins, e.g 682 670 ctx cooccurence:667
Rv0690c hyp hypothetical protein 621 621 ctx neighborhood:596
Rv2425c hyp hypothetical protein 553 554 ctx cooccurence:536
Rv2750 dehydrogenase 762 465 ctx cooccurence:461 textmining:575
Rv0687 NAD-dependent oxidoreductase 746 434 ctx cooccurence:429 textmining:571
Rv0761c adhB alcohol dehydrogenase B 749 277 textmining:668
Rv1162 narH nitrate reductase subunit beta 419 252
Rv1163 narJ nitrate reductase subunit delta 427 159

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: mycofactocin radical SAM maturase MftC
  • MTBC0 PGAP product: mycofactocin radical SAM maturase
  • Pfam (hmmscan --cut_ga): Radical_SAM PF04055.28 (E=2e-28), SPASM PF13186.12 (E=2e-06)
  • (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_215207.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Radical_SAM (PF04055.28), SPASM (PF13186.12)
  • 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 COG0535
  • Curated reference: UniProt P9WJ79 (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 — 22 functional partner(s); context anchor mftB
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000734|Rv0693|mftC
MTSPVPRLIEQFERGLDAPICLTWELTYACNLACVHCLSSSGKRDPGELSTRQCKDIIDELERMQVFYVNIGGGEPTVRPDFWELVDYATAHHVGVKFSTNGVRITPEVATRLAATDYVDVQISLDGATAEVNDAIRGTGSFDMAVRALQNLAAAGFAGVKISVVITRRNVAQLDEFATLASRYGATLRITRLRPSGRGTDVWADLHPTADQQVQLYDWLVSKGERVLTGDSFFHLAPLGQSGALAGLNMCGAGRVVCLIDPVGDVYACPFAIHDHFLAGNVLSDGGFQNVWKNSSLFRELREPQSAGACGSCGHYDSCRGGCMAAKFFTGLPLDGPDPECVQGHSEPALARERHLPRPRADHSRGRRVSKPVPLTLSMRPPKRPCNESPV