NaBGL1_candidate_BGLU18_6 is the best current NICAT mapping for the beta-GD1/NicGH late hydrolase step that releases nicotine from a glucosylated intermediate. The recent pathway paper mechanistically secures beta-GD1 as a core late enzyme, and the mapping dive now makes BGLU18_6 the strongest attenuata orthology anchor for that role.
Definition: Catalysis of the hydrolysis of a nicotine-pathway glucoside intermediate to release nicotine and beta-D-glucose during the late steps of nicotine biosynthesis.
Justification: The recent nicotine pathway paper resolves a specialized beta-GD1/NicGH function that is not captured by the generic beta-glucosidase activity term.
Parent term: beta-glucosidase activity
Supporting Evidence:
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004553 hydrolase activity, hydrolyzing O-glycosyl compounds | IEA GO_REF:0000120 | MODIFY | Summary: This parent hydrolase term should be collapsed to the more specific beta-glucosidase annotation. Reason: GO:0008422 captures the relevant GH1 catalytic specificity more directly. Proposed replacements: beta-glucosidase activity |
| GO:0005975 carbohydrate metabolic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This broad process term is too generic to express the pathway-specific conclusion. Reason: The more informative biology is a nicotine-pathway glucoside hydrolase role rather than generic carbohydrate metabolism. |
| GO:0008422 beta-glucosidase activity | IEA GO_REF:0000118 | ACCEPT | Summary: This is the core catalytic annotation for the BGLU18_6 candidate. Reason: UniProt and GH1 family assignment support beta-glucosidase chemistry, and the pathway paper makes beta-GD1 the late nicotine hydrolase. Supporting Evidence: file:NICAT/NaBGL1_candidate_BGLU18_6/NaBGL1_candidate_BGLU18_6-notes.md The glucosylation preprint makes beta-GD1/NicGH a mechanistically defined late nicotine-pathway hydrolase by placing it in the A622-MATE1-beta-GD1 cluster and using UGT1, A622, BBLa, and beta-GD1 to reconstitute the four-enzyme nicotine synthase cascade. |
| GO:0042179 nicotine biosynthetic process | TAS file:NICAT/NaBGL1_candidate_BGLU18_6/NaBGL1_candidate_BGLU18_6-notes.md | NEW | Summary: BGLU18_6 should be added as the leading nicotine-pathway beta-glucosidase candidate. Reason: The paper identifies beta-GD1/NicGH as a core late hydrolase and the mapping pass places BGLU18_6 as the best current attenuata ortholog. Supporting Evidence: file:NICAT/NaBGL1_candidate_BGLU18_6/NaBGL1_candidate_BGLU18_6-notes.md The 2026-04-05 mapping dive assigns NaBGL1 to BGLU18_6 / A0A1J6KFZ7 as the best current sequence-backed NICAT ortholog to tobacco beta-GD1, and explicitly demotes the older BGLU42 launch to a weaker historical comparator. |
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Download this section (compressed HTML)Q: Does A0A1J6KFZ7 account for most NicGH flux in Nicotiana attenuata roots, or is there meaningful redundancy with the beta-GD2-like copy?
Q: What exact glucosylated late intermediate is preferred by the attenuata BGLU18_6 candidate?
Experiment: Reconstitute BGLU18_6 with the UGT1-A622-BBL module and test hydrolysis of the resulting late nicotine glucosides.
Hypothesis: BGLU18_6 is the principal attenuata NicGH ortholog and efficiently hydrolyzes the pathway nicotine glucoside.
Type: pathway reconstitution assay
Experiment: Knock out the BGLU18_6 candidate and measure nicotine glucoside accumulation together with nicotine depletion after induction.
Hypothesis: Loss of BGLU18_6 will cause buildup of late glucosylated intermediates and reduce nicotine output.
Type: genetic perturbation plus metabolite profiling
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