Using single molecule fluorescence resonance energy transfer, we investigated the interaction between a quadruplex-binding ligand and the human telomeric G-quadruplex. The binding of quinolinecarboxamide macrocycle to telomeric DNA was essentially irreversible and selectively induced and favored one quadruplex conformation. The ligand-quadruplex complex displayed intramolecular dynamics includi...

The structural competition between the G-quadruplex and Watson-Crick duplex has been implicated for the repetitive DNA sequences, but the factors influencing this competitive equilibrium in the natural and pharmacological context need to be elucidated. Using a 21mer 5'-Fluorescein-d[(G3TTA)3G3]-TAMRA-3' as a model system, extensive fluorescence resonance energy transfer analysis was carried out...

Non-canonical guanine quadruplex structures are not only predominant but also conserved among bacterial and mammalian promoters. Moreover recent findings directly implicate quadruplex structures in transcription. These argue for an intrinsic role of the structural motif and thereby posit that single nucleotide polymorphisms (SNP) that compromise the quadruplex architecture could influence funct...

Demonstration of the existence of G-quadruplex structures in telomeres of Stylonychia macronuclei and in the promoter of c-myc in human cells has validated these secondary DNA structures as potential targets for drug design. The next important issue is the selectivity of G-quadruplex-interactive agents for the different types of G-quadruplex structures. In this study, we have taken an important...

The structure polymorphism of human telomeric G-quadruplex (ht-quadruplex) is currently an important topic but remains controversy. Here, we present study of the ht-quadruplex under the cation-deficient but molecular crowding conditions by circular dichroism (CD), microchip electrophoresis (MCE) and UV-melting experiments. Our results show that with concentration increasing of poly(ethylene gly...

Selectivity, binding stoichiometry, and mode of binding of Tel01, distamycin A, and diethylthiocarbocyanine iodide (DTC) to the parallel stranded G4-quadruplex [d(T2G5T)]4 were investigated by ESI-MS. The first drug/quadruplex complexes observed by ESI-MS are described. Tel01, distamycin A, and DTC all form complexes with quadruplex DNA, but only Tel01 is completely selective for quadruplex ver...