Conformational Properties of a Phototautomerizable Nucleoside Biomarker for Phenolic Carcinogen Exposure
Bibliographic record
Abstract
We have characterized the conformational properties of the C8-deoxyguanosine (C8-dG) nucleoside adduct, 8-(2"-hydroxyphenyl)-2'-dG (1), which is a potential biomarker for exposure to phenolic carcinogens. Adduct 1 possesses the unique ability to phototautomerize, through an excited-state intramolecular proton transfer (ESIPT) process, to generate its keto form. This tautomerization depends on the presence of an intramolecular hydrogen (H)-bond between the phenolic OH and the imine nitrogen (N7) and has permitted insight into the equilibrium ground states of adduct 1. The results of our studies demonstrate that adduct 1 undergoes an ESIPT despite preferring a nonplanar "twisted" conformation that is imposed by the deoxyribose (dR) sugar moiety. Interestingly, a planar conformation of adduct 1 is also formed in certain aprotic solvents due to the anchoring effect of the intramolecular H-bond. Our results provide a basis for future studies aimed at determining the conformations of adduct 1 within DNA that will aid in our understanding of phenol-mediated carcinogenesis.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".