The design and synthesis of metal complexes that can specifically target DNA secondary structure has attracted considerable attention. Chiral metallosupramolecular complexes (e.g. helicates) in particular display unique DNA-binding behavior, however until recently few examples which are both water-compatible and enantiomerically pure have been reported. Herein we report that one metallohelix en...

Effects of natural isoflavones on the structural competition of human telomeric G-quadruplex d[AG(3)(T(2)AG(3))(3)] and its related Watson-Crick duplex d[AG(3)(T(2)AG(3))(3)-(C(3)TA(2))(3)C(3)T] are investigated by using circular dichroism (CD), ESI-MS, fluorescence quenching measurement, CD stopped-flow kinetic experiment, UV spectroscopy and molecular modeling methods. It is intriguing to fin...

The process of in vitro selection has led to the discovery of many aptamers with potential to be developed into inhibitors and biosensors, but problems in isolating aptamers against certain targets with desired affinity and specificity still remain. One possible improvement is to use libraries enhanced for motifs repeatedly isolated in aptamer molecules. One such frequently observed motif is th...

The use of small molecules to arrest G-quadruplex structure has become a potential strategy for the development and design of a new class of anticancer therapeutics. We have studied the interaction of myricetin, a plant flavonoid and a putative anticancer agent, with human telomeric G-quadruplex TTAGGG(TTAGGG)3 DNA. Reverse transcription PCR data revealed significant repression in hTERT express...

G-quadruplex structures formed in the telomeric DNA are thought to play a role in the telomere function. Drugs that stabilize the G-quadruplexes were shown to have anticancer effects. The structures formed by the basic telomeric quadruplex-forming unit G(3)(TTAG(3))(3) were the subject of multiple studies. Here, we employ (125)I-radioprobing, a method based on analysis of the distribution of DN...

We report that the cationic porphyrin TmPyP4, which is known mainly as a DNA G-quadruplex stabilizer, unfolds an unusually stable all purine RNA G-quadruplex (M3Q) that is located in the 5'-UTR of MT3-MMP mRNA. When the interaction between TmPyP4 and M3Q was monitored by UV spectroscopy a 22-nm bathochromic shift and 75% hypochromicity of the porphin major Soret band was observed indicating dir...

O6-alkylguanine-DNA alkyltransferase (AGT) is a single-cycle DNA repair enzyme that removes promutagenic O6-alkylguanine adducts from DNA. Its functions with short single-stranded and duplex substrates have been characterized, but its ability to act on other DNA structures remains poorly understood. Here, we examine the functions of this enzyme on O6methylguanine (6mG) adducts in the four-stran...

Described is the structure-based design and synthesis of a series of tris-triazole G-quadruplex binding ligands utilising the copper catalysed azide-alkyne 'click' reaction. The results of G-quadruplex stabilisation by the ligands are reported and discussed.

Replacement of deoxyguanosine (dG) nucleobases within G-tetrads of G-quadruplex folding oligonucleotides with donor (D)/acceptor (A) fluorescent 8aryldG residues provides diagnostic FRET signalling for G-quadruplex detection.

We report herein the use of an exonuclease III and G-quadruplex probe to construct a G-quadruplex-based luminescence detection platform for Hg2+. Unlike common DNA-based Hg2+ detection methods, when using the dsDNA probe to monitor the hairpin formation, the intercalation of the dsDNA probe may be influenced by the distortion of dsDNA. This 'mix-and-detect' methodology utilized the G-quadruplex...