Synthesis of α-Deoxymono and Difluorohexopyranosyl 1-Phosphates and Kinetic Evaluation with Thymidylyl- and Guanidylyltransferases
Bibliographic record
Abstract
Eight fluorinated isosteric α- d -glucopyranosyl 1-phosphate ( Glc 1P ) analogues have been synthesized. A promiscuity investigation of the thymidylyltransferase Cps2L and the guanidylyltansferase GDP-ManPP with these analogues showed that all were accepted by either enzyme, with the exception of 1,6-diphosphate 6 . Kinetic parameters were determined for these analogues using a continuous coupled assay. These data demonstrated the broad substrate promiscuity of Cps2L, with k cat / K m changes for monofluoro substitution at C-2, C-4, and C-6 and difluoro substitution at C-2 within two orders of magnitude. In contrast, the kinetic analysis of GDP-ManPP was only possible with three out of eight analogues. The p K a 2 values of analogues ( 1 – 3 ) were determined by proton decoupled 31 P and 19 F NMR titration experiments. Counterintuitively, the axial fluoro substituent in 3 did not change chemical shift upon titration, and there was no significant increase in acidity for the difluoro analogue over the monofluoro analogues. No strong Brønsted linear free-energy correlations were observed among all five substrates ( 1 – 3, Glc 1P, and Man 1P ) for either enzyme-catalyzed reactions. However, Brønsted correlations were observed among selected substrates, indicating that the acidity of the nucleophilic phosphate and the configuration of the hexose each plays a significant role in determining the substrate specificity.
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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 | 0.001 | 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 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".