nirD Family assigned · medium auto-curated

H37Rv Rv0253 · MTBC0 mtbc0_000269 · 118 aa · 305835–306191 (+) · RefSeq NP_214767.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)nitrite reductase small subunit NirD
MTBC0 PGAP re-annotationnitrite reductase small subunit NirD
Revised (this work)Nitrite reductase small subunit NirD. Pfam: Rieske_2 (PF13806.13).

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

Curated reference (UniProt)

UniProt O53675 TrEMBL · unreviewed · Evidence at protein level
UniProt nameNitrite reductase
EC (curated) EC 1.7.1.15
Curated functionRequired for activity of the reductase.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category P Inorganic ion transport and metabolism
Preferred namenirD
eggNOG descriptionNitrite reductase
Orthologous groupCOG2146
EC number EC 1.7.1.15
KEGG orthology K00363
KEGG pathways map00910, map01120
KEGG modules M00530

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 0.357 · purifying
Polymorphic sites (≥ 0.1% of strains) 2 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
Rieske_2PF13806.13 3.0e-3610–113 Rieske-like [2Fe-2S] domain

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

Closest characterised functional partner: nirB (nitrite reductase large subunit NirB), high confidence from genomic context alone (score 1000 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv0252 nirB nitrite reductase large subunit NirB 999 1000 ctx neighborhood:844 cooccurence:774 coexpression:919 experimental:434 database:900 textmining:768
Rv1162 narH nitrate reductase subunit beta 978 951 coexpression:517 database:900 textmining:585
Rv1161 narG nitrate reductase subunit alpha 964 942 coexpression:430 database:900 textmining:410
Rv1164 narI nitrate reductase subunit gamma 965 941 coexpression:418 database:900 textmining:430
Rv1736c narX nitrate reductase-like protein NarX 953 941 coexpression:417 database:900
Rv0267 narU nitrite extrusion protein NarU 962 938 database:900 textmining:425
Rv2329c narK1 nitrate/nitrite transporter 971 936 database:900 textmining:575
Rv0261c narK3 nitrate/nitrite transporter 952 936 database:900
Rv1737c narK2 nitrate/nitrite transporter 946 932 database:900
Rv2222c glnA2 glutamine synthetase 924 902 database:900
Rv1878 glnA3 glutamine synthetase GlnA 907 902 database:900
Rv2220 glnA1 glutamine synthetase 929 901 database:900
Rv2860c glnA4 glutamine synthetase 906 901 database:900
Rv2476c gdh NAD-dependent glutamate dehydrogenase 902 900 database:900
Rv2781c oxidoreductase 900 900 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: nitrite reductase small subunit NirD
  • MTBC0 PGAP product: nitrite reductase small subunit NirD
  • Pfam (hmmscan --cut_ga): Rieske_2 PF13806.13 (E=3e-36)
  • (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_214767.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Rieske_2 (PF13806.13)
  • 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 COG2146
  • Curated reference: UniProt O53675 (TrEMBL, unreviewed; 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 — 35 functional partner(s); context anchor nirB
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000269|Rv0253|nirD
MTLLNDIQVWTTACAYDHLIPGRGVGVLLDDGSQVALFRLDDGSVHAVGNVDPFSGAAVMSRGIVGDRGGRAMVQSPILKQAFALDDGSCLDDPRVSVPVYPARVTPEGRIQVARVAV