The E358S mutant of <i>Agrobacterium</i> sp. β‐glucosidase is a greatly improved glycosynthase
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Glycosynthases are nucleophile mutants of retaining glycosidases that catalyze the glycosylation of sugar acceptors using glycosyl fluoride donors, thereby synthesizing oligosaccharides. The 'original' glycosynthase, derived from Agrobacterium sp. beta-glucosidase (Abg) by mutating the nucleophile glutamate to alanine (E358A), synthesizes oligosaccharides in yields exceeding 90% [Mackenzie, L.F., Wang, Q., Warren, R.A.J. and Withers, S.G. (1998) J. Am. Chem. Soc. 120, 5583-5584]. This mutant has now been re-cloned with a His(6)-tag into a pET-29b(+) vector, allowing gram scale production and single step chromatographic purification. A dramatic, 24-fold, improvement in synthetic rates has also been achieved by substituting the nucleophile with serine, resulting in improved product yields, reduced reaction times and an enhanced synthetic repertoire. Thus poor acceptors for Abg E358A, such as PNP-GlcNAc, are successfully glycosylated by E358S, allowing the synthesis of PNP-beta-LacNAc. The increased glycosylation activity of Abg E358S likely originates from a stabilizing interaction between the Ser hydroxyl group and the departing anomeric fluorine of the alpha-glycosyl fluoride.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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 it