Conformational analysis in aqueous solution and estimation of the persistence length of exopolysaccharides produced by <i>Lactobacillus helveticus</i> Lh59 and <i>Streptococcus macedonicus</i> Sc136
Bibliographic record
Abstract
The conformations of two exopolysaccharides, one produced by Lactobacillus helveticus Lh59 and one by Streptococcus macedonicus Sc136, were investigated by molecular modelling to get insight into their physical properties. In particular, the influence of side chains and glycosidic linkage types on the overall shapes and persistence lengths of the polysaccharides were studied. It appeared that the side chains had only minor effects on the persistence lengths of the polysaccharides, with the exception of the monosaccharide residue directly attached to the backbone. The extensiveness of the backbone is enhanced by β-D-Hexp-(1→4) structural elements, whereas α-D-Hexp-(1→3) and α-D-Hexp-(1→4) elements create structural variability by introducing bends. The occurrence of either (1→5)- or (1→6)-linked monosaccharides, resulting in one extra bond between monosaccharide units, causes the overall flexibility of the polysaccharide chain to be enhanced and extensiveness to be reduced. The presence of such flexible linkages in the backbone leads to a shorter persistence length than when present in the side chain: a value of only 4.5 nm was found for the L. helveticus Lh59 EPS with a (1→5) linkage in the backbone, and a value of 8.5 nm for the S. macedonicus Sc136 EPS with two (1→6) linkages in the side chain.Key words: conformational analysis, exopolysaccharide, Lactobacillus helveticus, molecular modelling, persistence length, Streptococcus macedonicus.
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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".