mku Resolved · high auto-curated

H37Rv Rv0937c · MTBC0 mtbc0_000995 · 273 aa · 1048416–1049237 (-) · RefSeq NP_215452.1

Annotation: from legacy to revised

Legacy (H37Rv / Mycobrowser)non-homologous end joining protein Ku
MTBC0 PGAP re-annotationKu protein
Revised (this work)Ku protein. Pfam: Ku (PF02735.23).

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

Curated reference (UniProt)

UniProt P9WKD9 SwissProt · reviewed · Evidence at protein level
UniProt nameNon-homologous end joining protein Ku
Curated functionWith LigD forms a non-homologous end joining (NHEJ) repair enzyme. Binds linear dsDNA with 5'- and 3'-overhangs but not closed circular dsDNA nor ssDNA. One dimer binds for every 30 bp. Recruits and stimulates the ligase activity of LigD but not of T4 ligase or a human ligase complex (LIG4/XRCC4). Attenuates the 3'- to 5'-exonuclease activity of LigD. Stimulates the template-directed addition of dNTPs by LigD on 5'-overhangs and nuclease activity on 3'-overhangs.

Functional vocabulary (eggNOG-mapper, orthology transfer)

COG category L Replication, recombination and repair
Preferred nameku
eggNOG descriptionWith LigD forms a non-homologous end joining (NHEJ) DNA repair enzyme, which repairs dsDNA breaks with reduced fidelity. Binds linear dsDNA with 5'- and 3'- overhangs but not closed circular dsDNA nor ssDNA. Recruits and stimulates the ligase activity of LigD
Orthologous groupCOG1273
KEGG orthology K10979
KEGG pathways map03450
Gene Ontology (39) GO:0000726, GO:0003674, GO:0003676, GO:0003677, GO:0003690, GO:0005488, GO:0006139, GO:0006259, GO:0006281, GO:0006302, GO:0006303, GO:0006725 +27 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 0.176 · strong purifying
Polymorphic sites (≥ 0.1% of strains) 5 synonymous, 3 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
KuPF02735.23 4.9e-5311–194 Ku70/Ku80 beta-barrel domain

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

Closest characterised functional partner: ligD (multifunctional non-homologous end joining DNA repair protein/ATP dependent DNA ligase LigD), high confidence from genomic context alone (score 954 excluding text-mining).

PartnerProductScoreNo text-miningChannels (≥400)
Rv0938 ligD multifunctional non-homologous end joining DNA repair protein/ATP dependent DNA ligase LigD 997 954 ctx neighborhood:628 cooccurence:774 coexpression:501 textmining:956
Rv3730c ligD hyp hypothetical protein 927 864 ctx cooccurence:773 coexpression:404 textmining:489
Rv0269c hyp hypothetical protein 898 864 ctx cooccurence:773 coexpression:402
Rv3731 ligC DNA ligase C 983 840 ctx cooccurence:765 textmining:901
Rv0949 uvrD1 ATP-dependent DNA helicase UvrD 876 722 database:720 textmining:575
Rv3062 ligB DNA ligase 889 674 ctx cooccurence:578 textmining:674
Rv0939 bifunctional 2-hydroxyhepta-2,4-diene-1,7-dioate isomerase/cyclase/dehydrase 597 597 ctx neighborhood:591
Rv3198c uvrD2 ATP-dependent DNA helicase UvrD 669 543 database:540
Rv3202c adnA ATP-dependent DNA helicase 568 541 database:540
Rv3201c adnB ATP-dependent DNA helicase 568 541 database:540
Rv2737c recA recombinase A 603 44 textmining:603
Rv0667 rpoB DNA-directed RNA polymerase subunit beta 493 44 textmining:492
Rv3014c ligA DNA ligase A 415 41 textmining:416

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: non-homologous end joining protein Ku
  • MTBC0 PGAP product: Ku protein
  • Pfam (hmmscan --cut_ga): Ku PF02735.23 (E=5e-53)
  • (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_215452.1)
  • Domains: Pfam-A via hmmscan --cut_ga — Ku (PF02735.23)
  • 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 COG1273
  • Curated reference: UniProt P9WKD9 (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 — 13 functional partner(s); context anchor ligD
  • Primary literature: none located yet; annotation rests on the domain/homology sources above.

Ancestral MTBC0 protein sequence

>mtbc0_000995|Rv0937c|mku
MRAIWTGSIAFGLVNVPVKVYSATADHDIRFHQVHAKDNGRIRYKRVCEACGEVVDYRDLARAYESGDGQMVAITDDDIASLPEERSREIEVLEFVPAADVDPMMFDRSYFLEPDSKSSKSYVLLAKTLAETDRMAIVHFTLRNKTRLAALRVKDFGKREVMMVHTLLWPDEIRDPDFPVLDQKVEIKPAELKMAGQVVDSMADDFNPDRYHDTYQEQLQELIDTKLEGGQAFTAEDQPRLLDEPEDVSDLLAKLEASVKARSKANSNVPTPP