NaAO2_candidate_AO_0 is one of the two current NICAT aspartate oxidase candidates for the duplicated pyridine branch feeding nicotine biosynthesis. It clearly encodes an L-aspartate oxidase in chloroplast-localized NAD precursor metabolism, but the available evidence does not yet distinguish AO_0 from AO_1 as the specialized nicotine-pathway paralog.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0008734 L-aspartate oxidase activity | IEA GO_REF:0000120 | ACCEPT | Summary: This is the specific catalytic activity supported for AO_0. Reason: UniProt and family assignment consistently identify AO_0 as an L-aspartate oxidase rather than a generic oxidoreductase. Supporting Evidence: file:NICAT/NaAO2_candidate_AO_0/NaAO2_candidate_AO_0-notes.md UniProt curates A0A1J6KBX2 as an L-aspartate oxidase/NadB-family flavoprotein that catalyzes oxidation of L-aspartate to iminoaspartate, linking this candidate to the upstream NAD branch that feeds pyridine alkaloid biosynthesis. |
| GO:0009435 NAD+ biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: AO_0 belongs in NAD biosynthesis. Reason: Aspartate oxidase catalyzes the upstream reaction that feeds de novo NAD biosynthesis, which is the ancestral source pathway for the pyridine branch. Supporting Evidence: file:NICAT/NaAO2_candidate_AO_0/NaAO2_candidate_AO_0-notes.md UniProt curates A0A1J6KBX2 as an L-aspartate oxidase/NadB-family flavoprotein that catalyzes oxidation of L-aspartate to iminoaspartate, linking this candidate to the upstream NAD branch that feeds pyridine alkaloid biosynthesis. |
| GO:0009507 chloroplast | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: Chloroplast localization is plausible and should be retained as non-core context. Reason: The location is supported in UniProt, but the main curation question for this candidate is paralog assignment within the pathway rather than subcellular detail. Supporting Evidence: file:NICAT/NaAO2_candidate_AO_0/NaAO2_candidate_AO_0-uniprot.txt CC -!- SUBCELLULAR LOCATION: Plastid, chloroplast |
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This parent oxidoreductase term is true but not specific enough. Reason: The more informative catalytic term GO:0008734 already captures the actual chemistry of AO_0. Supporting Evidence: file:NICAT/NaAO2_candidate_AO_0/NaAO2_candidate_AO_0-notes.md UniProt curates A0A1J6KBX2 as an L-aspartate oxidase/NadB-family flavoprotein that catalyzes oxidation of L-aspartate to iminoaspartate, linking this candidate to the upstream NAD branch that feeds pyridine alkaloid biosynthesis. |
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Download this section (compressed HTML)Q: Which of the AO_0 and AO_1 paralogs is preferentially induced in nicotine-producing roots after topping or herbivory?
Q: Does only one AO paralog measurably feed the pyridine branch used for nicotine accumulation?
Experiment: Compare AO_0 and AO_1 transcript abundance across roots, leaves, and induction time courses relevant to nicotine biosynthesis.
Hypothesis: One AO paralog is preferentially associated with nicotine-producing root tissue.
Type: expression profiling
Experiment: Create single-paralog knockouts and measure NAD intermediates, nicotinic acid branch metabolites, and nicotine accumulation.
Hypothesis: The pathway-specialized AO paralog will have a stronger effect on nicotine precursor supply.
Type: genetic perturbation plus metabolite profiling
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