Fluorine at the C5 Position of 2′‐Deoxyuridine Enhances Repair of a <i>O</i><sup>4</sup>‐Methyl Adduct by <i>O</i><sup>6</sup>‐Alkylguanine DNA Alkyltransferases
Bibliographic record
Abstract
Alkylation damage at the O6‐ and O4‐atoms of 2′‐deoxyguanosine (dG) and thymidine (T), respectively, can be removed by O6‐alkylguanine‐DNA alkyltransferases (AGTs). Previous studies have shown that human AGT (hAGT) repairs small adducts poorly at the O4‐atom of T, in comparison to the E. coli variants (OGT and Ada‐C). The C5 methyl group of the thymine nucleobase is suspected to contribute to hAGT repair proficiency possibly due to steric effects in the protein active site. In the present study, repair of oligonucleotides containing a 5‐fluoro‐O4‐methyl‐2′‐deoxyuridine (dFU‐Me) insert by hAGT, E. coli AGT variants (OGT and Ada‐C) and a chimeric hAGT/OGT protein was evaluated. All AGT variants, particularly hAGT and the hAGT/OGT chimera, demonstrated improved proficiency at removing the O4‐methyl group from substrates containing dFU‐Me, relative to the thymidine and 2′‐deoxyuridine counterparts.
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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".