Guanine-rich nucleic acids can form G-quadruplexes that are important in gene regulation, biosensor design and nano-structure construction. In this article, we report on the development of a nanopore encapsulating single-molecule method for exploring how cations regulate the folding and unfolding of the G-quadruplex formed by the thrombin-binding aptamer (TBA, GGTTGGTGTGGTTGG). The signature bl...

A G-quadruplex-based switch-on luminescence assay has been developed for the detection of gene deletion using a cyclometallated iridium(III) complex as a G-quadruplex-selective probe. Upon hybridization with the target DNA, the two split G-quadruplex-forming sequences assemble into a split G-quadruplex, which greatly enhances the luminescence emission of the iridium(III) probe. The assay is sim...

Interferon-inducible protein 16 (IFI16) is a member of the HIN-200 protein family, containing two HIN domains and one PYRIN domain. IFI16 acts as a sensor of viral and bacterial DNA and is important for innate immune responses. IFI16 binds DNA and binding has been described to be DNA length-dependent, but a preference for supercoiled DNA has also been demonstrated. Here we report a specific pre...

Ligands targeting telomeric G-quadruplexs are considered good candidates for anticancer drugs. However, current studies on G-quadruplex ligands focus exclusively on the interactions of ligands and monomeric G-quadruplexes under dilute conditions. Living cells are crowded with biomacromolecules, and the ≈ 200-nucleotide G-rich single-stranded overhang of human telomeric DNA has the potential to ...

Background In stabilization of the G-quadruplex, formation of a Hoogsteen base-pair between the guanine (G) bases is essential. However, the contribution of each Hoogsteen base-pair at different positions to whole stability of the G-quadruplex has not been known. In this study, the effect of a deficiency of the Hoogsteen type hydrogen bond in the G-quadruplex stability was investigated. Spectra...

We introduce designed ankyrin repeat binding proteins (DARPins) as a novel class of highly specific and structure-selective DNA-binding proteins, which can be functionally expressed within all cells. Human telomere quadruplex was used as target to select specific binders with ribosome display. The selected DARPins discriminate the human telomere quadruplex against the telomeric duplex and other...

Six novel di-substituted phenanthroline derivatives 5a-7a and 3b-5b have been prepared, and their binding interactions with human telomeric (h-telo) and promoter (c-kit2 and c-myc) G-quadruplex DNAs were investigated. All the compounds are potent stabilisers of the G-quadruplex structures and compounds 3b, 4b, and 5b exhibit high G-quadruplex DNA selectivity over duplex DNA. The binding affinit...

Abstract: Guanine-rich nucleic acids are able to self-assemble into G-quadruplex four-stranded secondary structures, which are found at the level of telomeric regions of chromosomes, oncogene promoter sequences and other biologically-relevant regions of the genome. Due to their extraordinary stiffness and biological role, G-quadruples become relevant in areas ranging from structural biology to ...

Telomere length homeostasis is a prerequisite for the generation and growth of cancer. In >85% cancer cells, telomere length is maintained by telomerase that add telomere repeats to the end of telomere DNA. Because the G-rich strand of telomere DNA can fold into G-quadruplex that inhibits telomerase activity, stabilizing telomere quadruplex by small molecules is emerging as a potential therapeu...

Piperine, a naturally occurring alkaloid, is well known as anti-oxidant, anti-mutagenic, anti-tumor and anti-proliferative agent. Piperine exerts such pharmacological activities by binding or interacting with various cellular targets. Recently, the first report for Piperine interaction with duplex DNA has been published last year but its interaction with G-quadruplex structures has not been stu...