The effects of stereochemistry and sequence on 5-t-butylproline type VI β-turn mimics
Bibliographic record
Abstract
Steric interactions can control peptide geometry favoring particular secondary structures. We have examined the effects of steric bulk on peptide turn geometry by synthesizing N-acetyl-LXaa-5-t-butylproline -methylamides and their natural proline counterparts which were analyzed by NMR and CD spectroscopy as well as X-ray diffraction [1]. The prolyl amide trans-isomer was favored in the peptides containing natural proline, which were found not to adopt specific turn geometries in solution. In contrast, the L-Xaa-Pro amide cis-isomer was favored in the case of the 5-t-butylprolyl peptides, which adopted preferably type VIa conformations. Because the type conformation is often adopted by peptides possessing D-amino acids N-terminal to proline at the central turn residues [2], we synthesized N-acetyl-D-Xaa-5-t-butylproline -methylamides.These compounds were used to examine whether, by favoring the prolyl amide cis-isomer, the bulky 5-t-butyl substituent could disrupt the type geometry and induce a type VI
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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".