Combination of a Dinuclear Zn<sup>2+</sup>Complex and a Medium Effect Exerts a 10<sup>12</sup>-Fold Rate Enhancement of Cleavage of an RNA and DNA Model System
Bibliographic record
Abstract
The catalytic ability of a dinuclear Zn2+ complex of 1,3-bis-N1-(1,5,9-triazacyclododecyl)propane (3) in promoting the cleavage of an RNA model, 2-hydroxypropyl-p-nitrophenyl phosphate (HPNPP, 1), and a DNA model, methyl p-nitrophenyl phosphate (MNPP, 4), was studied in methanol solution in the presence of added CH3O- at 25 degrees C. The di-Zn2+ complex (Zn2 :3), in the presence of 1 equiv of added methoxide, exhibits a second-order rate constant of (2.75 +/- 0.10) x 10(5) M(-1) s(-1) for the reaction with 1 at s(s)pH 9.5, this being 10(8)-fold larger than the k2 value for the CH3O- promoted reaction (kOCH3 = (2.56 +/- 0.16) x 10(-3) M(-1) s(-1)). The complex is also active toward the DNA model 4, exhibiting Michaelis-Menten kinetics with a KM and kmax of 0.37 +/- 0.07 mM and (4.1 +/- 0.3) x 10(-2) s(-1), respectively. Relative to the background reactions at s(s)pH 9.5, Zn2 :3 accelerates cleavage of each phosphate diester by a remarkable factor of 1012-fold. A kinetic scheme common to both substrates is discussed. The study shows that a simple model system comprising a dinuclear Zn2+ complex and a medium effect of the alcohol solvent achieves a catalytic reactivity that approaches enzymatic rates and is well beyond anything seen to date in water for the cleavage of these phosphate diesters.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".