Strictosidine Synthase Triggered Enantioselective Synthesis of N-Substituted (<i>S</i>)-3,14,18,19-Tetrahydroangustines as Novel Topoisomerase I Inhibitors
Bibliographic record
Abstract
Monoterpenoid indole alkaloids (MIAs) comprise an important class of molecules for drug discovery, and they have variant carbon skeletons with prominent bioactivities. For instance, in spite of limitations to their use, camptothecins are the only clinically approved topoisomerase I (Top1) inhibitors. The enzyme strictosidine synthase, which is key for MIA biosynthesis, was applied to the enantioselective preparation of three N-substituted (S)-3,14,18,19-tetrahydroangustine (THA) derivatives. These non-camptothecin MIAs were shown to have moderate in vitro HepG2 cytotoxicity and Top1 inhibition activities. The (S)-configured MIAs had stronger cytotoxicity and Top1 inhibition than their chemically synthesized (R)-enantiomers, which aligned with the results of molecular dynamics simulations. A series of N-substituted (S)-THAs were then chemoenzymatically synthesized to investigate structure-activity relationships. The most active analogue observed was the N-(2-Cl benzoyl)-substituted derivative (7i). Insight into the binding mode of 7i and a Top1-DNA covalent complex was investigated by molecular dynamics simulations, which will facilitate future efforts to optimize the Top1 inhibitory activities of non-camptothecin MIAs.
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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 | 0.001 |
| 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".