Screening and characterization of variant Theta‐class glutathione transferases catalyzing the activation of ethylene dibromide to a mutagen
Bibliographic record
Abstract
Ethylene dibromide (EDB) is a widespread environmental pollutant and mutagen/carcinogen. Certain Theta-class glutathione transferases (GSTs), enzymes that catalyze the reaction of reduced glutathione (GSH) with electrophiles, activate EDB to a mutagen. Previous studies have shown that human GST T1-1, but not rat GST T2-2, activates EDB. We have constructed an E. coli lacZ reversion mutagenicity assay system in which expression of recombinant GST supports activation of EDB to a mutagen. Hexa-histidine N-terminal tagging of GST T1-1 results in greatly enhanced expression of the recombinant enzyme and gives a lacZ strain that shows a mutagenic response to EDB at extremely low levels (approximately 1 ng EDB per plate). The hexa-histidine-tagged enzyme was purified in one step by Ni(2+)-affinity chromatography. We applied the lacZ mutagenicity assay to the rapid screening of a library of variant GST Theta enzymes. Sequence variants with altered catalytic activities were identified, purified, and characterized.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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".