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Record W7133060124

Chemical and biochemical characterization of multistranded guanine-rich DNA supramolecules

2000· dissertation· W7133060124 on OpenAlexfundno aff
Karen Poon

Bibliographic record

VenueTSpace · 2000
Typedissertation
Language
FieldBiochemistry, Genetics and Molecular Biology
TopicDNA and Nucleic Acid Chemistry
Canadian institutionsnot available
FundersUniversity of TorontoGovernment of Ontario
KeywordsGuanineDNANucleic acidBase pairTetradIntermolecular forceReactivity (psychology)StoichiometryStacking
DOInot available

Abstract

fetched live from OpenAlex

An alternative platform technology for modifying nucleic acid structure without changing its original chemical DNA structure is examined. In this platform, multiple DNA strands interact by non-covalent bonding to form a new structure of DNA supramolecule. This thesis focuses on the study of multistranded guanine-rich DNA supramolecules that are stabilized by guanine-guanine interactions. Structural variations are observed among DNA supramolecules formed by different guanine-rich oligonucleotides. The guanine-guanine interactions in DNA complexes formed by telomere-like sequences, for example d(T15G4T2G4), are different from that in the complex formed by d(T15G15 ) called frayed wires. A new type of intermolecular Multistrand Guanine-Guanine interaction (MGG) is found to exist contributing to the stabilization of frayed wires. This MGG interaction can be differentiated from the canonical guanine tetrad through both strand association stoichiometry and chemical reactivity of dimethyl sulphate at the N7 site of guanine. The MGG interaction observed in frayed wires does not require the N7 sites of the guanine bases to form stable complexes; therefore, methylation by dimethyl sulphate at N7 sites does not hinder the formation of frayed wires. This phenomenon does not occur in complexes stabilized by guanine tetrads. The manifestation of different guanine-guanine interactions arises from two factors: the number of contiguous guanines and the availability of the N7 sites in the guanine base in the sequence. The thermal stability of the d(T15Gn) DNA complexes is determined by various factors. These factors include the nature of guanine-guanine interaction, the number and arrangement of the contiguous guanines within the DNA sequences, and the balance between the stabilization force of the guanine bases versus the unfavorable contribution of the non-guanine portion within the oligonucleotide sequences. Our data indicate that frayed wires are resistant to enzymatic degradation by common nucleases. Ligands bound to frayed wires are also protected from degradation. Frayed wires stabilized by MGG interaction may be used as a carrier for biologically active molecules.

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.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation 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 score0.001
Threshold uncertainty score0.004

Distilled classifier scores by category (both heads)

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)0.0010.000

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 head0.006
GPT teacher head0.266
Teacher spread0.261 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

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".

Quick stats

Citations0
Published2000
Admission routes1
Has abstractyes

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