Rapid Single-Shot Synthesis of the 217 Amino Acid-Long N-Terminal Domain of Pyocin S2
Bibliographic record
Abstract
Abstract The impermeable outer membrane of Pseudomonas aeruginosa is bypassed by antibacterial proteins known as S-type pyocins. Because of their properties, pyocins are investigated as a potential new class of antimicrobials against Pseudomonas infections. Their production and modification, however, remains challenging. To address this limitation, we employed automated fast-flow peptide synthesis (AFPS) for the rapid production of a pyocin S2 import domain. The N-terminal domain sequence (PyS2 NTD ) was synthesized in under 10 hours and purified to yield milligrams quantities of the desired product. To our knowledge, the 217 amino acid sequence of PyS2 NTD is among the longest peptides produced from a “single-shot” synthesis, i.e., made in a single stepwise route without the use of ligation techniques. Biophysical characterization of the PyS2 NTD with circular dichroism was consistent with the literature reports. Fluorescently labeled PyS2 NTD binds to P. aeruginosa expressing the cognate ferripyoverdine receptor (FpvA) and is taken up into the periplasm. This selective uptake was validated with confocal and super resolution microscopy, flow cytometry, and fluorescence recovery after photobleaching (FRAP). These modified, synthetic S-type pyocins domains can be used to probe import mechanisms of P. aeruginosa and leveraged to develop selective antimicrobial agents that bypass the outer membrane.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".