Volumetric characterization of homopolymeric amino acids
Bibliographic record
Abstract
We have determined the partial molar volumes, expansibilities, and adiabatic compressibilities for poly(L-alanine), poly(L-proline), and poly(L-threonine) within the temperature range of 18-55 degrees C. In addition, we have determined at 25 degrees C changes in volume, DeltaV, and adiabatic compressibility, DeltaK(S), associated with the coil-to-helix transitions of poly(L-lysine) and poly(L-glutamic acid) and the alpha-to-beta transition of poly(L-lysine). We have interpreted our volumetric data as suggesting that poly(L-alanine) and poly(L-proline) are not fully unfolded and, probably, retain some solvent-inaccessible core. Further, we propose that poly(L-threonine) is fully unfolded with the majority of its atomic groups being solvent-exposed. Near zero changes in volume and compressibility accompanying the coil-to-helix transitions of poly(L-lysine) and poly(L-glutamic acid) suggest that, in the absence of fortuitous compensations, the coil-to-helix transitions of the polypeptides do not result in any significant enhancement of solute hydration. By contrast, the alpha-to-beta transition of poly(L-lysine) causes slight but statistically significant increases in volume and compressibility, an observation that may suggest that the beta-sheet conformation of poly(L-lysine) is slightly less hydrated than its alpha-helical conformation. In general, our results provide a quantitative volumetric description of the hydration properties of the homopolymeric polypeptides investigated. Such characterizations should prove useful in developing an understanding of the role that solvent plays in the stabilization/destabilization of folded protein structures and protein complexes.
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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".