An in Vitro–Selected DNAzyme Mutant Highly Specific for Na<sup>+</sup> under Slightly Acidic Conditions
Bibliographic record
Abstract
Abstract Sodium is one of the most common metal ions in biology; however, DNA‐based sodium probes have only been reported recently. A Na + ‐specific RNA‐cleaving DNAzyme named NaA43 is active with Na + alone. In this work, we were using Co(NH 3 ) 6 3+ as the intended metal cofactor for in vitro selection, but obtained a mutant of the NaA43 DNAzyme. The mutant was named NaH1, and differs from NaA43 by only two nucleotides. NaA43 has an optimal pH of 7.0, whereas the optimal pH for NaH1 is 6.0. This difference might be due to our selection having been performed at pH 6.0. NaH1 also displays an excellent selectivity for sodium relative to other competing monovalent ions, as well as a fast catalytic rate of (0.11±0.01) min −1 with 50 m m Na + . At low Na + concentrations, the selected DNAzyme exhibited a higher cleavage rate than NaA43 and thus a tighter apparent K d of (12.0±1.6) m m Na + . Furthermore, the NaH1 DNAzyme was engineered into a fluorescent Na + biosensor by attaching a fluorophore/quencher pair to the DNAzyme with a detection limit of 223 μ m Na + . Preliminary work on detection of Na + in serum was demonstrated as well. This study provides a useful mutant that works in a slightly acidic environment, which might be useful for sensing Na + in acidic in vivo environments.
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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".