Evidence for Two Populated Conformations for the Dimeric Le<sup>X</sup> and Le<sup>A</sup>Le<sup>X</sup> Tumor-Associated Carbohydrate Antigens
Bibliographic record
Abstract
The conformational behavior of tumor-associated carbohydrate antigens (TACAs) dimLe(x) and Le(a)Le(x) was studied using a combination of NMR experiments and molecular dynamics simulations. It is shown that within the hexasaccharides, the Le(x) and Le(a) branched trisaccharide fragments adopt the rigid "stacked" conformation known for the isolated trisaccharide antigens. In contrast, the β-D-GlcNAc-(1→3)-D-Gal glycosidic bond that connects the two Le(x) trisaccharides in dimLe(x), and the Le(a) trisaccharide to the Le(x) trisaccharide in Le(a)Le(x), was found to be very flexible in both hexasaccharides. Our results show that two distinct conformations, differing by the value of the Ψ angle for this glycosidic bond, are populated in solution. While the relative proportions of the two conformations in solution could not be determined accurately, experimental measurements indicate that both conformations are populated in significant amounts.
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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) | 0.002 | 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".