Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3'-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T(4)G(4)), forms a 16-nucleotide 3'-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformations in vitro. Although it has been prop...

A family of terpyridine metallo-organic complexes has been designed and its recognition properties of G-quadruplex-DNA investigated. The series combines easy synthetic access and good affinity-selectivity ratio for quadruplex-DNA. Our study also highlights that the geometry of the metal center strongly governs the ability of the compounds to discriminate quadruplex from duplex-DNA.

An RNA G-quadruplex library was synthesised and screened against kanamycin A as the ligand. Naturally occurring G-quadruplex forming sequences that differentially bind to kanamycin A were identified and characterized. This provides a simple and effective strategy for identification of potential intracellular G-quadruplex targets for a ligand.

G-quadruplex unfolding within a sequence of two quadruplex units was characterized by gel electrophoresis, calorimetry and spectroscopy. The obtained results suggest that the kinetics and thermodynamics of the individual quadruplex unfolding are affected by its interaction with other DNA secondary structural elements.

Ligands that can interact specifically with telomeric multimeric G-quadruplexes could be developed as promising anticancer drugs with few side effects related to other G-quadruplex-forming regions. In this paper, a new cationic porphyrin derivative, m-TMPipEOPP, was synthesized and characterized. Its multimeric G-quadruplex recognition specificity under molecular crowding conditions was compare...

A study on binding of antitumor chelerythrine to human telomeric DNA/RNA G-quadruplexes was performed by using DNA polymerase stop assay, UV-melting, ESI-TOF-MS, UV-Vis absorption spectrophotometry and fluorescent triazole orange displacement assay. Chelerythrine selectively binds to and stabilizes the K(+)-form hybrid-type human telomeric DNA G-quadruplex of biological significance, compared w...

The G-quadruplex is an alternative DNA structural motif that is considered to be functionally important in the mammalian genome for transcriptional regulation, DNA replication and genome stability, but the nature and distribution of G-quadruplexes across the genome remains elusive. Here, we address the hypothesis that G-quadruplex structures exist within double-stranded genomic DNA and can be e...

Nuclear magnetic resonance study of G-quadruplex structures formed by d(TG(3)T) and its modified analogs containing a 5'-5' or 3'-3' inversion of polarity sites, namely d(3'TG5'-5'G(2)T3'), d(3'T5'-5'G(3)T3') and d(5'TG3'-3'G(2)T5') demonstrates formation of G-quadruplex structures with tetrameric topology and distinct cation-binding preferences. All oligonucleotides are able to form quadruplex...

The interactions of a series of platinum(II) Schiff base complexes with c-myc G-quadruplex DNA were studied. Complex [PtL(1a)] (1 a; H(2)L(1a)=N,N'-bis(salicylidene)-4,5-methoxy-1,2-phenylenediamine) can moderately inhibit c-myc gene promoter activity in a cell-free system through stabilizing the G-quadruplex structure and can inhibit c-myc oncogene expression in cultured cells. The interaction...

Telomestatin (TMS: 1) is as a potent and selective telomeric G-quadruplex binder. Two molecules of TMS were suggested to be intercalated to one telomeric G-quadruplex according to docking study. In this paper, we designed and synthesized hexaoxazole TMS derivative (6OTD) dimer, and evaluated its G-quadruplex stabilizing ability.