ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Differences in affinity of arylstilbazolium derivatives to tetraplex structures
Izabella Czerwinska and Bernard Juskowiak
Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland
Abstract: Research into the interactions of small molecules (ligands) with DNA is a very important field of biochemistry. A ligand interacts
with a DNA structure in many ways, depending on the structural features of the ligand (the presence of rings, substituent
groups, length of bonds, etc.) or nucleic acid (number and association of strands, base sequence etc.). This study reports
on an investigation of the preferential binding of arylstilbazolium ligands to a four-stranded DNA. For this purpose, an equilibrium
dialysis was used. Equilibrium dialysis is a versatile method which enables many DNA structures to be investigated at the
same time. A dozen different DNA structures of (single-stranded, double-stranded (duplex), triple-stranded (triplex), and
four-stranded (tetraplex)) were involved in experiments with each ligand. Following the dissociation of DNA-ligand complexes
by SDS, the concentration of the ligand bound was calculated from fluorescence and absorbance calibration curves. As a result,
the amount of the ligand bound was directly related to the ligand-binding affinity. Equilibrium dialysis was used as a powerful
tool to indicate which of the arylstilbazolium ligands investigated was the best therapeutic agent targeting G-quadruplex.
Arylstilbazolium derivatives demonstrated strong interactions with the DNA samples used in the assay. The most interesting
finding was a selective, preferential binding of anthryl derivative to c-MYC DNA (c-MYC is a DNA sequence that appears in
an oncogene). Furthermore, as this derivative binds preferentially to one of the triplexes investigated, it can find an application
in the TFO-triplex forming oligonucleotides which are used in gene therapy.
Keywords: G-quadruplexes – arylstilbazolium ligands – DNA-ligand interactions – equilibrium dialysis method
Full paper is available at www.springerlink.com.
Chemical Papers 65 (2) 242–245 (2011)