Structure elucidation and biological activities of two classes of peptides produced by the actinomycete, Kitasatospora cystarginea
Bibliographic record
Abstract
Kitasatospora is a rare genus of Actinobacteria that represents an underexplored resource for the discovery of structurally diverse natural products. To highlight the production of unique metabolites produced by twelve members of this genus, the chemical screening method that combines LC-HRMS with Principal Component Analysis (PCA) was used. This approach identified the production of three novel compounds by K. cystarginea ; which were determined to be a lipopeptide and two β-lactone containing peptide analogs, referred to as cystargamide and cystargolides A and B. Their structures were elucidated using NMR and MS/MS, and absolute configurations using advanced Marfey's Method. The therapeutic potential of cystargamide and cystargolides A and B were evaluated in several bioassays. Most notably, cystargolides A and B displayed inhibition of human 20S proteasome with IC 50 values of 0.35 and 0.93µM respectively.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| 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 | 0.000 | 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 source (direct Gemma or distilled Codex), 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".