FTIR study of a nonclassical dT10*dA10-dT10 intramolecular triple helix.

  title={FTIR study of a nonclassical dT10*dA10-dT10 intramolecular triple helix.},
  author={C. Dagneaux and Jean Liquier and E. Taillandier},
  volume={34 45},
Many early investigations on triple helices have been devoted to the study of the triplex formed by dT*dA-dT base triplets in which the third strand is oriented parallel to the dA strand. We now describe an intramolecular triple helix with dT*dA-dT base triplets in which the pyrimidine third strand is oriented antiparallel, formed by folding back twice the tridecamer dT10-linker-dA10-linker-dT10 (linker = pO(CH2CH2O)3p). Third-strand base pairing to the target strand, sugar conformation, and… 

Parallel and antiparallel A*A-T intramolecular triple helices.

An energetically optimized model of the parallel A*A-T triple helix with a non-uniform distribution of sugar conformations is discussed and the experimental results and molecular modeling data are consistent with a reverse-Hoogsteen like third-strand base pairing and South-type sugar conformation.

A physico-chemical study of triple helix formation by an oligodeoxythymidylate with N3'--> P5' phosphoramidate linkages.

The results indicate that the pentadecadeoxythymidylate with phosphoramidate linkages [dT15(np)] is highly potent to form a triple helix with a dT15*dA15target duplex through Hoogsteenbase-pairing.

Recombination R-triplex: H-bonds contribution to stability as revealed with minor base substitutions for adenine

The enthalpy of the 10 nt long intramolecular triplex of −100 kJ·mol−1 demonstrates that the R-triplex is relatively unstable and thus an ideal candidate for a transient intermediate in homologous recombination, t-loop formation at the mammalian telomere ends, and short RNA invasion into a duplex.

FTIR and UV Spectroscopy Studies of Triplex Formation Between Pyrimidine Methoxyethylphosphoramidates α- Oligodeoxynucleotides and ds DNA Targets

Thermal stability of the formed complexes was studied by UV thermal denaturation and the data showed that these PNHME α-ODNs formed much more stable triplexes than phosphodiester (PO) β- ODNs did.

FTIR and UV Spectroscopy Studies of Triplex Formation Between α-Oligonucleotides with Non-Ionic Phoshoramidate Linkages and DNA Targets

All αdCTPN strands form triplexes even at neutral pH, and it is shown by FTIR spectroscopy that the triplex formed at pH 7 is held by Hoogsteen T*A.T triplets and in addition by an hydrogen bond between O6 of G and C of the third strand.

One-electron oxidation of TAT-motif triplex DNA and the ensuing Hoogsteen hydrogen-bonding dissociation.

Investigation of the deprotonation behavior of A•+ in the TAT triplex with continuous A bases by time-resolved laser flash photolysis provides valuable kinetic data and in-depth mechanistic insights for understanding the adenine oxidative DNA damage in the triplex.

Conformational study of DNA-RNA duplexes containing MMI substituted phosphodiester linkages by FTIR spectroscopy.

It is postulate that the observed preorganization of the sugar residues and oligonucleotides containing 2'-modified MMI modifications may play an important role in both improving the recognition of RNA target and enhancing the stability of duplex formation with RNA.

Progress in developments of triplex-based strategies.

Progress has been made toward developing general procedures to determine the molecular mechanisms of action of triplex-forming oligonucleotides (TFO) administered to cultured cells to provide a rational proof-of-concept for antigene strategies.

Mechanism of copper mediated triple helix formation at neutral pH in Drosophila satellite repeats.

It is demonstrated here how, under nearly physiological pH conditions, Drosophila melanogaster AAGAGAG satellite sequence can form a pyrimidine triple helix containing T.A-T and CCu.G-C base triplets, stabilized by Cu2+ metal ions in amounts mirroring in vivo concentrations.