sdhC Family assigned · medium auto-curated

H37Rv Rv3316 · MTBC0 mtbc0_003526 · 112 aa · 3726240–3726578 (+) · RefSeq NP_217833.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)succinate dehydrogenase cytochrome B-556 subunit
MTBC0 PGAP re-annotationsuccinate dehydrogenase%2C cytochrome b556 subunit
Revised (this work)Succinate dehydrogenase%2C cytochrome b556 subunit. Pfam: Sdh_cyt (PF01127.28).

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

Curated reference (UniProt)

UniProt O53368 SwissProt · reviewed · Evidence at protein level
UniProt nameSuccinate dehydrogenase 2 membrane subunit SdhC
Curated functionMembrane-anchoring subunit of succinate dehydrogenase 2 (Sdh2). Sdh2 may catalyze the two-electron oxidation of succinate to fumarate with a corresponding reduction of quinone to quinol under low oxygen conditions, when the primary aerobic succinate dehydrogenase (Sdh1) is inhibited. Sdh2 seems to be the generator of the proton motive force (PMF) under hypoxia.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category C Energy production and conversion
Preferred namesdhC
eggNOG descriptionsuccinate dehydrogenase
Orthologous groupCOG2009
KEGG orthology K00241
KEGG pathways map00020, map00190, map00650, map00720, map01100, map01110, map01120, map01130, map01200
KEGG modules M00009, M00011, M00149, M00173, M00374, M00376

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 0.314 · purifying
Polymorphic sites (≥ 0.1% of strains) 1 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)

PfamAccessioni-EvalueResiduesDescription
Sdh_cytPF01127.28 1.5e-171–96 Succinate dehydrogenase/Fumarate reductase transmembrane subunit

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

Closest characterised functional partner: sdhA (succinate dehydrogenase flavoprotein subunit), high confidence from genomic context alone (score 1000 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv3318 sdhA succinate dehydrogenase flavoprotein subunit 999 1000 ctx neighborhood:758 cooccurence:736 coexpression:664 experimental:870 database:960 textmining:967
Rv3319 sdhB succinate dehydrogenase iron-sulphur protein subunit 999 1000 ctx neighborhood:758 cooccurence:766 coexpression:698 experimental:997 database:962 textmining:909
Rv3317 sdhD succinate dehydrogenase hydrophobic membrane anchor subunit 999 1000 ctx neighborhood:881 cooccurence:774 coexpression:865 experimental:997 database:900 textmining:937
Rv1553 frdB fumarate reductase iron-sulfur subunit 999 998 coexpression:694 experimental:788 database:962 textmining:653
Rv0247c succinate dehydrogenase iron-sulfur subunit 999 998 coexpression:696 experimental:788 database:962 textmining:861
Rv1552 frdA fumarate reductase flavoprotein subunit 998 997 coexpression:650 experimental:707 database:960 textmining:614
Rv0248c succinate dehydrogenase flavoprotein subunit 999 996 coexpression:652 experimental:707 database:960 textmining:812
Rv0951 sucC succinyl-CoA ligase subunit beta 986 982 coexpression:811 database:900
Rv0952 sucD succinyl-CoA ligase subunit alpha 980 974 coexpression:726 database:900
Rv1248c kgd multifunctional 2-oxoglutarate dehydrogenase E1 component /2-oxoglutarate dehydrogenase dihydrolipoyllysine-residue succinyltransferase 983 961 coexpression:953 textmining:588
Rv3537 kstD 3-oxosteroid 1-dehydrogenase 962 959 coexpression:650 experimental:707 database:621
Rv1817 flavoprotein 962 959 coexpression:650 experimental:707 database:621
Rv1098c fum fumarate hydratase 959 947 coexpression:490 database:900
Rv1731 gabD2 succinate-semialdehyde dehydrogenase 911 910 database:900
Rv0234c gabD1 succinate-semialdehyde dehydrogenase 910 909 database:900

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: succinate dehydrogenase cytochrome B-556 subunit
  • MTBC0 PGAP product: succinate dehydrogenase%2C cytochrome b556 subunit
  • Pfam (hmmscan --cut_ga): Sdh_cyt PF01127.28 (E=2e-17)
  • (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_217833.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Sdh_cyt (PF01127.28)
  • 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 COG2009
  • Curated reference: UniProt O53368 (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 — 109 functional partner(s); context anchor sdhA
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_003526|Rv3316|sdhC
MWSWVCHRISGATIFFFLFVHVLDAAMLRVSPQTYNAVLATYKTPIVGLMEYGLVAAVLFHALNGIRVILIDFWSEGPRYQRLMLWIIGSVFLLLMVPAGVVVGIHMWEHFR