Discovery of a Novel Class II Lasso Peptide from Streptomyces sp. RKKD-790
Bibliographic record
Abstract
Streptomyces sp. RKKD-790 produces a novel class II lasso peptide consisting of 15 amino acids. The lasso fold is formed by the C-terminal tail irreversibly threading through a macrolactam ring formed between glycine at the N-terminus and aspartic acid at the eighth amino acid position. The threaded structure is held in place by Trp-14 and Leu-15 which act as bulky steric locks that prevent the linear tail from unthreading. Lasso peptides are extremely stable due to this threaded structure and make effective molecular scaffolds for drug design. This is the smallest lasso peptide isolated to date and provides an example of the minimum structural features required to form the knotted structure. It was discovered by analyzing LCMS profiles of a library of bacterial fermentation extracts using the multivariate statistic tool Principal Component Analysis. The structure was elucidated using NMR spectroscopy and the lasso fold was determined using tandem mass spectrometry and computational modeling from NOE distance constraints. The discovery, isolation and structure elucidation of this novel peptide will be presented.
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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) | 0.001 | 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".