Impact of Glycosylation on Saccharomyces cerevisiae Endopolygalacturonase PGU1 Activity and Stability
Bibliographic record
Abstract
Endopolygalacturonases are among the best selling enzymes for a number of commercial applications such as food processing. For such enzymes, a potentially important component of production cost is glycosylation. This important modification of endopolygalacturonase has been detected for a number of species, but its real importance has not been thoroughly studied. Here we investigated endopolygalacturonase PGU1 from Saccharomyces cerevisiae CECT 1389 produced in S. cerevisiae INVSc 1. Combinatorial mutagenesis of recombinant S. cerevesiae PGU1 putative glycosylation sites was performed, where asparagines 318 and 330 were replaced with either aspartic acid or glutamine. Electrophoretic analysis of the different recombinant enzymes studied here demonstrates that the putative sites 318 and 330 are indeed glycosylated when produced in S. cerevesiae INVSc 1. The optimal activity of these enzymes was detected at pH 4.5 and 55-60 ºC. As for stability, all enzymes studied were less than 50% active after an incubation of two hours at 50 ºC and at pH between 4.5 and 6.0. Glycosylation did not provide any significant stabilisation of PGU1, but the replacement of Asn 330 with Gln had a deleterious effect on stability. The secondary structure spectra are characteristics of proteins mostly composed of beta sheets. The T m values measured for PGU1, PGU1 deglycosylated with endo H, and three mutants ranged from 53 to 55.4ºC, indicating that glycosylation had no impact on PGU1 conformation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 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 teacher head, 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".