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M-DNA: pH Stability, Nuclease Resistance and Signal Transmission

2000· article· en· W2081549806 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueJournal of Biomolecular Structure and Dynamics · 2000
Typearticle
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicRNA and protein synthesis mechanisms
Canadian institutionsUniversity of Saskatchewan
Fundersnot available
KeywordsDNAChemistryBase pairBiochemistry

Abstract

fetched live from OpenAlex

Abstract In the presence of divalent metal ions (Zn(2)+, Co(2)+, and Ni(2)+) and at pHs above 8, duplex DNA forms a complex called M-DNA. M-DNA can be converted back to B-DNA by addition of EDTA or lowering the pH. The stability of M-DNA depends on the metal ion and/or the sequence of DNA. For calf thymus DNA the order of stability with decreasing pH is: Ni(2+)> Co(2+)>Zn(2++). The interconversion with B-DNA shows hysteresis; once formed Ni-M- DNA remains stable for more than one hour at pH 7, but conversion of B-DNA to M-DNA is slow at pHs below 8. Among synthetic sequences, poly[d(AT)] does not form M-DNA whereas the phosphorothioate analogues form only at pH 9.0. In contrast, the Ni-M-DNA form of poly[d(GC)] is stable even at pH 6.5. Ni-M-DNA is resistant to cleavage by DNase I whereas B-DNA is digested rapidly under identical conditions. The Co(2)+ and Ni(2+) forms of M-DNA were paramagnetic with increased mass susceptibilities (χ) compared to other metal complexes. Signal transmission in M-DNA was tested by constructing duplexes of 54 base pairs with fluorescein (donor) at one end and rhodamine (acceptor) at the other. Quenching of fluorescein fluorescence was observed for the Zn(2+) form of M-DNA only when the DNA was labeled with both donor and acceptor. Therefore, the pathway of quenching maybe via electron transfer. Taken together, these results suggest that M-DNA is a distinct conformation with tightly bound metal ions, and certain forms may be stable under physiological conditions. Furthermore, M-DNA may be used as a molecular wire for signal transmission over long distances.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.071
Threshold uncertainty score0.513

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.004
GPT teacher head0.203
Teacher spread0.200 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it