qcrC Resolved · high auto-curated

H37Rv Rv2194 · MTBC0 mtbc0_002330 · 280 aa · 2483560–2484402 (+) · RefSeq NP_216710.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)ubiquinol-cytochrome C reductase cytochrome subunit C
MTBC0 PGAP re-annotationcytochrome c
Revised (this work)Cytochrome c. Pfam: Cytochrom_C (PF00034.27), Cytochrome_CBB3 (PF13442.12).

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

Curated reference (UniProt)

UniProt P9WP35 SwissProt · reviewed · Evidence at protein level
UniProt nameCytochrome bc1 complex cytochrome c subunit
EC (curated) EC 7.1.1.8
Curated functionCytochrome b subunit of the cytochrome bc1 complex, an essential component of the respiratory electron transport chain required for ATP synthesis. The bc1 complex catalyzes the oxidation of ubiquinol and the reduction of cytochrome c in the respiratory chain. The bc1 complex operates through a Q-cycle mechanism that couples electron transfer to generation of the proton gradient that drives ATP synthesis.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category C Energy production and conversion
Preferred nameqcrC
eggNOG descriptioncytochrome C
Orthologous groupCOG2010
KEGG orthology K03889
KEGG pathways map00190, map01100
KEGG modules M00151
Gene Ontology (14) GO:0005575, GO:0005623, GO:0005886, GO:0005887, GO:0008150, GO:0016020, GO:0016021, GO:0031224, GO:0031226, GO:0040007, GO:0044425, GO:0044459 +2 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 0.712 · relaxed/neutral
Polymorphic sites (≥ 0.1% of strains) 3 synonymous, 6 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
Cytochrom_CPF00034.27 4.4e-0864–137 Cytochrome c
Cytochrome_CBB3PF13442.12 1.4e-08163–235 Cytochrome C oxidase, cbb3-type, subunit III

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

Closest characterised functional partner: ctaC (cytochrome C oxidase subunit II), high confidence from genomic context alone (score 1000 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv2200c ctaC cytochrome C oxidase subunit II 999 1000 ctx cooccurence:637 coexpression:401 experimental:999 textmining:850
Rv3043c ctaD cytochrome C oxidase cytochrome 1 999 1000 experimental:999 textmining:919
Rv2196 qcrB ubiquinol-cytochrome C reductase cytochrome subunit B 999 1000 ctx neighborhood:881 cooccurence:773 coexpression:816 experimental:999 database:900 textmining:933
Rv2195 qcrA ubiquinol-cytochrome C reductase rieske iron-sulfur subunit 999 1000 ctx neighborhood:881 cooccurence:773 coexpression:929 experimental:999 database:900 textmining:965
Rv2199c ctaF cytochrome c oxidase polypeptide 4 999 1000 ctx cooccurence:774 experimental:999 textmining:434
Rv2193 ctaE cytochrome C oxidase subunit III 999 1000 ctx neighborhood:822 cooccurence:559 coexpression:823 experimental:999 textmining:879
Rv2876 transmembrane protein 999 999 experimental:999
Rv0685 tuf elongation factor Tu 941 931 experimental:921
Rv3584 lpqE lipoprotein LpqE 962 913 experimental:902 textmining:592
Rv0432 sodC superoxide dismutase 871 872 experimental:870
Rv2468A hyp hypothetical protein 870 870 experimental:870
Rv0863 hyp hypothetical protein 867 868 experimental:848
Rv1162 narH nitrate reductase subunit beta 859 811 experimental:790
Rv1161 narG nitrate reductase subunit alpha 854 801 experimental:788
Rv1736c narX nitrate reductase-like protein NarX 828 801 experimental:788

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: ubiquinol-cytochrome C reductase cytochrome subunit C
  • MTBC0 PGAP product: cytochrome c
  • Pfam (hmmscan --cut_ga): Cytochrom_C PF00034.27 (E=4e-08), Cytochrome_CBB3 PF13442.12 (E=1e-08)
  • (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_216710.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Cytochrom_C (PF00034.27), Cytochrome_CBB3 (PF13442.12)
  • 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 COG2010
  • Curated reference: UniProt P9WP35 (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 — 104 functional partner(s); context anchor ctaC
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_002330|Rv2194|qcrC
MTKLGFTRSGGSKSGRTRRRLRRRLSGGVLLLIALTIAGGLAAVLTPTPQVAVADESSSALLRTGKQLFDTSCVSCHGANLQGVPDHGPSLIGVGEAAVYFQVSTGRMPAMRGEAQAPRKDPIFDEAQIDAIGAYVQANGGGPTVVRNPDGSIATQSLRGNDLGRGGDLFRLNCASCHNFTGKGGALSSGKYAPDLAPANEQQILTAMLTGPQNMPKFSNRQLSFEAKKDIIAYVKVATEARQPGGYLLGGFGPAPEGMAMWIIGMVAAIGLALWIGARS