glgB Resolved · high auto-curated
H37Rv Rv1326c · MTBC0 mtbc0_001423 ·
731 aa · 1500819–1503014 (-) ·
RefSeq NP_215842.1
Annotation: from legacy to revised
| Legacy (H37Rv / Mycobrowser) | 1,4-alpha-glucan branching protein |
|---|---|
| MTBC0 PGAP re-annotation | 1%2C4-alpha-glucan branching protein GlgB |
| Revised (this work) | 1%2C4-alpha-glucan branching protein GlgB. Pfam: GlgB_N (PF22019.3), CBM_48 (PF02922.25), Alpha-amylase (PF00128.32), Alpha-amylase_C (PF02806.25). |
Auto-curated: this verdict and function were generated by rules from PGAP + Pfam + Foldseek and have not been hand-reviewed.
Curated reference (UniProt)
| UniProt |
P9WN45
SwissProt · reviewed
· Evidence at protein level
|
|---|---|
| UniProt name | 1,4-alpha-glucan branching enzyme GlgB |
| EC (curated) |
EC 2.4.1.18
|
| Curated function | Essential enzyme that catalyzes the formation of the alpha-1,6-glucosidic linkages in glucan chains by scission of a 1,4-alpha-linked oligosaccharide from growing alpha-1,4-glucan chains and the subsequent attachment of the oligosaccharide to the alpha-1,6 position. Is involved in the biosynthesis of both glycogen and capsular alpha-D-glucan. |
Functional vocabulary (eggNOG-mapper, orthology transfer)
| COG category |
G Carbohydrate transport and metabolism
|
|---|---|
| Preferred name | glgB |
| eggNOG description | Catalyzes the formation of the alpha-1,6-glucosidic linkages in glycogen by scission of a 1,4-alpha-linked oligosaccharide from growing alpha-1,4-glucan chains and the subsequent attachment of the oligosaccharide to the alpha-1,6 position |
| Orthologous group | COG0296 |
| EC number |
EC 2.4.1.18
|
| KEGG orthology |
K00700
|
| KEGG pathways |
map00500, map01100, map01110
|
| KEGG modules |
M00565
|
| CAZy family |
CBM48, GH13
|
| Gene Ontology (43) |
GO:0000271, GO:0003674, GO:0003824, GO:0003844, GO:0005575, GO:0005623, GO:0005886, GO:0005975, GO:0005976, GO:0005977, GO:0005978, GO:0006073 +31 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 | 0.354 · purifying |
|---|---|
| Polymorphic sites (≥ 0.1% of strains) | 8 synonymous, 9 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)
| Pfam | Accession | i-Evalue | Residues | Description |
|---|---|---|---|---|
GlgB_N | PF22019.3 | 2.1e-25 | 16–104 | alpha-1,4-glucan branching enzyme GlgB, N-terminal domain |
CBM_48 | PF02922.25 | 2.5e-23 | 130–216 | Carbohydrate-binding module 48 (Isoamylase N-terminal domain) |
Alpha-amylase | PF00128.32 | 3.3e-09 | 280–348 | Alpha amylase, catalytic domain |
Alpha-amylase_C | PF02806.25 | 3.3e-25 | 633–730 | Alpha amylase, C-terminal all-beta domain |
Functional interaction network (STRING v12, guilt-by-association)
Closest characterised functional partner: glgE (alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase), high confidence from genomic context alone (score 999 excluding text-mining).
| Partner | Product | Score | No text-mining | Channels (≥400) |
|---|---|---|---|---|
Rv1327c glgE |
alpha-1,4-glucan:maltose-1-phosphate maltosyltransferase | 999 | 999 ctx | neighborhood:882 coexpression:844 database:900 textmining:965 |
Rv1328 glgP |
glycogen phosphorylase | 999 | 995 ctx | neighborhood:768 coexpression:732 database:900 textmining:937 |
Rv1781c malQ |
4-alpha-glucanotransferase | 997 | 991 ctx | fusion:736 cooccurence:441 coexpression:409 database:900 textmining:773 |
Rv1564c treX |
maltooligosyl trehalose synthase | 993 | 981 | coexpression:704 database:900 textmining:666 |
Rv3032 |
glycogen synthase | 997 | 977 | coexpression:410 database:955 textmining:890 |
Rv0127 mak |
maltokinase | 997 | 949 ctx | fusion:899 textmining:955 |
Rv1213 glgC |
glucose-1-phosphate adenylyltransferase | 997 | 944 ctx | cooccurence:763 coexpression:734 textmining:959 |
Rv0126 treS |
trehalose synthase/amylase TreS | 997 | 935 | database:900 textmining:965 |
Rv1212c glgA |
capsular glucan synthase | 995 | 910 | coexpression:410 database:777 textmining:954 |
Rv3068c pgmA |
phosphoglucomutase PgmA | 917 | 906 ctx | fusion:687 coexpression:696 |
Rv3031 |
1,4-alpha-glucan-branching protein | 987 | 903 | database:900 textmining:875 |
Rv2610c pimA |
alpha-(1-2)-phosphatidylinositol mannosyltransferase | 817 | 783 | coexpression:414 database:572 |
Rv2729c |
integral membrane protein | 805 | 782 | coexpression:411 database:572 |
Rv0806c cpsY |
exopolysaccharide phosphotransferase CpsY | 792 | 782 | coexpression:411 database:572 |
Rv2188c pimB |
alpha-(1-6)-phosphatidylinositol monomannoside mannosyltransferase | 819 | 781 | coexpression:407 database:572 |
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: 1,4-alpha-glucan branching protein
- MTBC0 PGAP product: 1%2C4-alpha-glucan branching protein GlgB
- Pfam (hmmscan --cut_ga): GlgB_N PF22019.3 (E=2e-25), CBM_48 PF02922.25 (E=3e-23), Alpha-amylase PF00128.32 (E=3e-09), Alpha-amylase_C PF02806.25 (E=3e-25)
- (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_215842.1)
- Domains: Pfam-A via hmmscan --cut_ga — GlgB_N (PF22019.3), CBM_48 (PF02922.25), Alpha-amylase (PF00128.32), Alpha-amylase_C (PF02806.25)
- 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
COG0296 - Curated reference: UniProt P9WN45 (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 —
52 functional partner(s); context anchor
glgE - Primary literature: none located yet; annotation rests on the domain/homology sources above.
Ancestral MTBC0 protein sequence
>mtbc0_001423|Rv1326c|glgB MSRSEKLTGEHLAPEPAEMARLVAGTHHNPHGILGAHEYGDHTVIRAFRPHAVEVVALVGKDRFSLQHLDSGLFAVALPFVDLIDYRLQVTYEGCEPHTVADAYRFLPTLGEVDLHLFAEGRHERLWEVLGAHPRSFTTADGVVSGVSFAVWAPNAKGVSLIGEFNGWNGHEAPMRVLGPSGVWELFWPDFPCDGLYKFRVHGADGVVTDRADPFAFGTEVPPQTASRVTSSDYTWGDDDWMAGRALRNPVNEAMSTYEVHLGSWRPGLSYRQLARELTDYIVDQGFTHVELLPVAEHPFAGSWGYQVTSYYAPTSRFGTPDDFRALVDALHQAGIGVIVDWVPAHFPKDAWALGRFDGTPLYEHSDPKRGEQLDWGTYVFDFGRPEVRNFLVANALYWLQEFHIDGLRVDAVASMLYLDYSRPEGGWTPNVHGGRENLEAVQFLQEMNATAHKVAPGIVTIAEESTSWPGVTRPTNIGGLGFSMKWNMGWMHDTLDYVSRDPVYRSYHHHEMTFSMLYAFSENYVLPLSHDEVVHGKGTLWGRMPGNNHVKAAGLRSLLAYQWAHPGKQLLFMGQEFGQRAEWSEQRGLDWFQLDENGFSNGIQRLVRDINDIYRCHPALWSLDTTPEGYSWIDANDSANNVLSFMRYGSDGSVLACVFNFAGAEHRDYRLGLPRAGRWREVLNTDATIYHGSGIGNLGGVDATDDPWHGRPASAVLVLPPTSALWLTPA