Pb<sup>2+</sup> as a Substrate and a Cofactor of a Porphyrin Metalation DNAzyme
Bibliographic record
Abstract
Abstract We herein report a DNAzyme named T30695 (sequence: (G 3 T) 4 ) that can catalyze Zn 2+ insertion into three different porphyrins in the presence of Pb 2+ as a cofactor. Meanwhile, T30695 with Pb 2+ alone was found to cause a shift in both the fluorescence and UV‐vis spectra of protoporphyrin IX (PPIX), thus suggesting that metalation of Pb 2+ was also achieved at room temperature. From kinetic measurements, the reaction required two Pb 2+ ions; this is consistent with one being a cofactor and the other being a substrate. No previous reports inserted Pb 2+ into porphyrins by using DNAzymes or protein‐based enzymes. This reaction was most significantly inhibited in the presence of K + followed by Na + and Li + , suggesting the importance of the Pb 2+ ‐stabilized G‐quadruplex. When Pb 2+ is inserted into PPIX, its emission blue shifts from 635 to 590 nm, thus allowing simple ratiometric fluorescent sensing with a detection limit of 1.2 nM Pb 2+ .
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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".