NaBGL1_candidate_BGLU42 is a lower-confidence historical GH1 beta-glucosidase comparator that was launched before the current mapping pass. The pathway paper secures beta-GD/NicGH biology at the family level, but the newer sequence-backed mapping now favors the BGLU18 pair rather than BGLU42 as the best current NICAT orthology anchors to the nicotine-pathway hydrolases.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0004553
hydrolase activity, hydrolyzing O-glycosyl compounds
|
IEA
GO_REF:0000002 |
MODIFY |
Summary: This parent hydrolase term should be replaced by the more specific beta-glucosidase term.
Reason: GO:0008422 already captures the relevant glycosidase specificity for this GH1 family enzyme.
Proposed replacements:
beta-glucosidase activity
|
|
GO:0005975
carbohydrate metabolic process
|
IEA
GO_REF:0000002 |
MARK AS OVER ANNOTATED |
Summary: This broad process term is true in a generic sense but not the informative curation takeaway.
Reason: The evidence that remains secure for this accession is generic GH1 beta-glucosidase chemistry rather than a specific pathway assignment.
|
|
GO:0008422
beta-glucosidase activity
|
IEA
GO_REF:0000120 |
ACCEPT |
Summary: This is an appropriate core molecular-function annotation.
Reason: UniProt identifies terminal beta-D-glucoside hydrolysis chemistry for this GH1 enzyme.
Supporting Evidence:
file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-uniprot.txt
Reaction=Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose.; EC=3.2.1.21;
|
|
GO:0009821
alkaloid biosynthetic process
|
IEA
GO_REF:0000117 |
REMOVE |
Summary: This pathway-process assignment is no longer strong enough for this specific accession.
Reason: The current mapping work indicates that BGLU42 is not the best orthology anchor to the specialized beta-GD pathway enzymes.
|
|
GO:0030245
cellulose catabolic process
|
IEA
GO_REF:0000002 |
REMOVE |
Summary: This appears to be an over-transfer from the broad GH1 family and should be removed.
Reason: This appears to be a generic GH1 family overcall rather than a reviewed biological role for BGLU42.
|
Q: Is BGLU42 completely outside the nicotine pathway, or does it retain any partial redundancy with the BGLU18 candidates?
Q: What substrates distinguish BGLU42 from the now-preferred BGLU18_6 and BGLU18_1 paralogs?
Experiment: Compare BGLU42 directly against BGLU18_6 and BGLU18_1 using nicotine-pathway glucosides and generic GH1 substrates.
Hypothesis: BGLU42 will show a substrate profile distinct from the preferred BGLU18 pathway candidates.
Type: biochemical substrate-specificity assay
Experiment: Disrupt BGLU42 alone and in combination with the BGLU18 candidates to test for any hidden redundancy in nicotine accumulation phenotypes.
Hypothesis: BGLU42 loss alone will have weaker nicotine-pathway effects than disruption of the BGLU18 candidates.
Type: genetic perturbation plus metabolite profiling
Upon thorough investigation, it appears that specific literature directly addressing the gene NaBGL1_candidate_BGLU42 (UniProt Accession: A0A314LBF6) in Nicotiana attenuata is limited or nonexistent. The gene symbol "NaBGL1_candidate_BGLU42" does not correspond to any well-characterized gene in current scientific databases. Consequently, detailed functional information specific to this gene is unavailable.
Protein Description and Family:
According to the UniProt entry A0A314LBF6, the protein is described as a beta-glucosidase belonging to the glycosyl hydrolase 1 (GH1) family. Beta-glucosidases are enzymes that catalyze the hydrolysis of β-D-glucosidic bonds, releasing non-reducing terminal glucosyl residues from glycosides and oligosaccharides. The GH1 family is characterized by specific conserved domains, including:
Glycosyl hydrolase family 1 (GH1) domain (IPR001360): This domain is associated with enzymes that hydrolyze glycosidic bonds between carbohydrates or between a carbohydrate and a non-carbohydrate moiety.
Glycosyl hydrolase 1 N-terminal domain (GH_1_N_CS) (IPR033132): This conserved site is typical of the N-terminal region of GH1 enzymes.
Beta-glucosidase active site (IPR017736): This domain includes the active site residues essential for the enzyme's catalytic function.
Inferred Function and Localization:
While direct experimental evidence for A0A314LBF6 is lacking, its classification within the GH1 family suggests that it functions as a beta-glucosidase. In plants, beta-glucosidases play crucial roles in various biological processes, including:
Defense Mechanisms: Beta-glucosidases are involved in the activation of defense compounds. For instance, in Nicotiana tabacum, overexpression of a beta-glucosidase gene led to increased accumulation of salicylic acid, a key signaling molecule in plant defense responses (pubmed.ncbi.nlm.nih.gov).
Secondary Metabolism: These enzymes participate in the hydrolysis of glycosylated secondary metabolites, thereby modulating their activity and availability.
Cell Wall Modification: Beta-glucosidases contribute to cell wall remodeling by degrading glucosidic bonds in cell wall components.
Regarding subcellular localization, beta-glucosidases can be found in various cellular compartments, including the cytoplasm, vacuole, and apoplast, depending on their specific functions and the plant species. Without specific data for A0A314LBF6, precise localization cannot be determined.
Pathway Involvement:
Beta-glucosidases are integral to several biochemical pathways:
Glycoside Hydrolysis: They hydrolyze glycosidic bonds in glycosides, releasing active aglycones that can participate in various metabolic processes.
Phytohormone Activation: Some beta-glucosidases are involved in the activation of phytohormones by hydrolyzing their inactive glucoside forms.
Defense Compound Activation: They can activate defense-related compounds by hydrolyzing their glycosylated precursors.
Conclusion:
In summary, while specific information on the gene NaBGL1_candidate_BGLU42 in Nicotiana attenuata is not available, its classification as a beta-glucosidase within the GH1 family allows us to infer potential functions based on domain analysis and the known roles of similar enzymes in plants. Experimental studies are necessary to elucidate the precise function, substrate specificity, localization, and pathway involvement of this particular beta-glucosidase in Nicotiana attenuata.
A0A314LBF6 as BGLU42, a glycosyl hydrolase family 1 beta-glucosidase with generic terminal beta-D-glucoside hydrolysis chemistry. [file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-uniprot.txt "DE SubName: Full=Beta-glucosidase 42"; "CC -!- CATALYTIC ACTIVITY: Reaction=Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose.; EC=3.2.1.21;"; "CC -!- SIMILARITY: Belongs to the glycosyl hydrolase 1 family."]NICAT accession corresponds to those specialized copies. [file:projects/NICOTINE_BIOSYNTHESIS/biorxiv-nicotine-glucosylation-notes.md "beta-GD1 = NicGH, a nicotine glucoside hydrolase"; "For the NICAT project, this paper is therefore strongest for pathway-role assignment and weakest for exact paralog/accession resolution."]NICAT orthology anchors to tobacco beta-GD1 and beta-GD2, so BGLU42 should be retained only as a lower-confidence historical comparator. [file:projects/NICOTINE_BIOSYNTHESIS.md "The already-launched NaBGL1_candidate_BGLU42 row should now be treated as a weaker historical comparator, not the best orthology anchor for the paper's beta-GD genes."; "NaBGL1 -> BGLU18_6 / A0A1J6KFZ7"; "NaBGL2 -> BGLU18_1 / A0A314KWB2"]id: A0A314LBF6
gene_symbol: NaBGL1_candidate_BGLU42
product_type: PROTEIN
status: DRAFT
aliases:
- BGLU42
- NaBGL1
taxon:
id: NCBITaxon:49451
label: Nicotiana attenuata
description: >-
NaBGL1_candidate_BGLU42 is a lower-confidence historical GH1 beta-glucosidase
comparator that was launched before the current mapping pass. The pathway paper
secures beta-GD/NicGH biology at the family level, but the newer sequence-backed
mapping now favors the BGLU18 pair rather than BGLU42 as the best current NICAT
orthology anchors to the nicotine-pathway hydrolases.
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000117
title: Electronic Gene Ontology annotations created by ARBA machine learning models
findings: []
- id: GO_REF:0000120
title: Combined Automated Annotation using Multiple IEA Methods
findings: []
- id: file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-uniprot.txt
title: UniProt entry A0A314LBF6 for Nicotiana attenuata BGLU42
findings:
- statement: BGLU42 is a glycosyl hydrolase family 1 beta-glucosidase
supporting_text: 'CC -!- CATALYTIC ACTIVITY:'
reference_section_type: DATABASE_ENTRY
- statement: UniProt assigns terminal beta-D-glucoside hydrolysis chemistry to BGLU42
supporting_text: Reaction=Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose.; EC=3.2.1.21;
reference_section_type: DATABASE_ENTRY
- id: file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-notes.md
title: NaBGL1 BGLU42 candidate notes
findings:
- statement: The glucosylation paper secures beta-GD-family hydrolase biology but not this accession specifically
supporting_text: The glucosylation preprint establishes beta-GD1/NicGH and the homeologous beta-GD2 as the relevant nicotine-pathway hydrolases, but it does not by itself resolve which current public NICAT accession corresponds to those specialized copies.
reference_section_type: LITERATURE_REVIEW
- statement: BGLU42 should now be treated as a weaker historical comparator
supporting_text: The 2026-04-05 mapping dive now favors BGLU18_6 and BGLU18_1 as the best sequence-backed NICAT orthology anchors to tobacco beta-GD1 and beta-GD2, so BGLU42 should be retained only as a lower-confidence historical comparator.
reference_section_type: LITERATURE_REVIEW
existing_annotations:
- term:
id: GO:0004553
label: hydrolase activity, hydrolyzing O-glycosyl compounds
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: This parent hydrolase term should be replaced by the more specific beta-glucosidase term.
action: MODIFY
reason: >-
GO:0008422 already captures the relevant glycosidase specificity for this
GH1 family enzyme.
proposed_replacement_terms:
- id: GO:0008422
label: beta-glucosidase activity
- term:
id: GO:0005975
label: carbohydrate metabolic process
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: This broad process term is true in a generic sense but not the informative curation takeaway.
action: MARK_AS_OVER_ANNOTATED
reason: >-
The evidence that remains secure for this accession is generic GH1
beta-glucosidase chemistry rather than a specific pathway assignment.
- term:
id: GO:0008422
label: beta-glucosidase activity
evidence_type: IEA
original_reference_id: GO_REF:0000120
review:
summary: This is an appropriate core molecular-function annotation.
action: ACCEPT
reason: >-
UniProt identifies terminal beta-D-glucoside hydrolysis chemistry for this
GH1 enzyme.
supported_by:
- reference_id: file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-uniprot.txt
supporting_text: Reaction=Hydrolysis of terminal, non-reducing beta-D-glucosyl residues with release of beta-D-glucose.; EC=3.2.1.21;
reference_section_type: DATABASE_ENTRY
- term:
id: GO:0009821
label: alkaloid biosynthetic process
evidence_type: IEA
original_reference_id: GO_REF:0000117
review:
summary: This pathway-process assignment is no longer strong enough for this specific accession.
action: REMOVE
reason: >-
The current mapping work indicates that BGLU42 is not the best orthology
anchor to the specialized beta-GD pathway enzymes.
- term:
id: GO:0030245
label: cellulose catabolic process
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: This appears to be an over-transfer from the broad GH1 family and should be removed.
action: REMOVE
reason: >-
This appears to be a generic GH1 family overcall rather than a reviewed
biological role for BGLU42.
core_functions:
- molecular_function:
id: GO:0008422
label: beta-glucosidase activity
directly_involved_in:
- id: GO:0005975
label: carbohydrate metabolic process
description: >-
BGLU42 is a GH1 beta-glucosidase retained as a lower-confidence comparator
while the BGLU18_6 and BGLU18_1 candidates are now preferred as the main
nicotine-pathway orthology anchors.
supported_by:
- reference_id: file:NICAT/NaBGL1_candidate_BGLU42/NaBGL1_candidate_BGLU42-notes.md
supporting_text: The 2026-04-05 mapping dive now favors BGLU18_6 and BGLU18_1 as the best sequence-backed NICAT orthology anchors to tobacco beta-GD1 and beta-GD2, so BGLU42 should be retained only as a lower-confidence historical comparator.
reference_section_type: LITERATURE_REVIEW
proposed_new_terms: []
suggested_questions:
- question: Is BGLU42 completely outside the nicotine pathway, or does it retain any partial redundancy with the BGLU18 candidates?
- question: What substrates distinguish BGLU42 from the now-preferred BGLU18_6 and BGLU18_1 paralogs?
suggested_experiments:
- description: Compare BGLU42 directly against BGLU18_6 and BGLU18_1 using nicotine-pathway glucosides and generic GH1 substrates.
experiment_type: biochemical substrate-specificity assay
hypothesis: BGLU42 will show a substrate profile distinct from the preferred BGLU18 pathway candidates.
- description: Disrupt BGLU42 alone and in combination with the BGLU18 candidates to test for any hidden redundancy in nicotine accumulation phenotypes.
experiment_type: genetic perturbation plus metabolite profiling
hypothesis: BGLU42 loss alone will have weaker nicotine-pathway effects than disruption of the BGLU18 candidates.