Two ubiquitous aldo-keto reductases in the genus Papaver support a patchwork model for morphine pathway evolution
Bibliographic record
Abstract
The evolution of morphinan alkaloid biosynthesis in plants of the genus Papaver includes permutation of several processes including gene duplication, fusion, neofunctionalization, and deletion resulting in the present chemotaxonomy. A critical gene fusion event resulting in the key bifunctional enzyme reticuline epimerase (REPI), which catalyzes the stereochemical inversion of (S)-reticuline, was suggested to precede neofunctionalization of downstream enzymes leading to morphine biosynthesis in opium poppy (Papaver somniferum). The ancestrally related aldo-keto reductases 1,2-dehydroreticuline reductase (DRR), which occurs in some species as a component of REPI, and codeinone reductase (COR) catalyze the second and penultimate steps, respectively, in the pathway converting (S)-reticuline to morphine. Orthologs for each enzyme isolated from the transcriptomes of 12 Papaver species were shown to catalyze their respective reactions in species that capture states of the metabolic pathway prior to key evolutionary events, including the gene fusion event leading to REPI, thus suggesting a patchwork model for pathway evolution. Analysis of the structure and substrate preferences of DRR orthologs in comparison with COR orthologs revealed structure-function relationships underpinning the functional latency of DRR and COR orthologs in the genus Papaver, thus providing insights into the molecular events leading to the evolution of the pathway.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".