Voltammetric characterization of human telomeric G-quadruplex: A label free method for anticancer drug detection.

Abstract

Human telomeric DNA typically consists of many tandem repeats of the guanine-rich sequences d (TTAGGG) termed an intermolecular Gquadruplex structure. This structure plays an important role in the protection, stabilization and replication of chromosome ends and so is an active target for therapeutic purposes. Recently ligands that are able to stabilize Gquadruplex structure, have received great attention because quadruplex-binding ligands have potential applications in cancer therapy. The screen-printed graphite electrode (SPE) was modified with synthesized SBA-N-propylpipyrazine-N-(2-mercaptopropane-1-one) (SBA-NPPNSH) mesoporous structure to investigate the Gquadruplex DNA (G4DNA) formation and stabilization. Differential pulse voltammetry was used to examine the stability and formation of G4DNA in various K(+) concentrations, under different pH conditions and also in the presence of positive and negative G4DNA-binding ligands. The stability effect of TMPyP4 as a positive G4DNA-binding ligand was examined in the presence of complementary G4DNA strands. This studying revealed that after adding K(+) or positive G4DNA-binding ligand a new peak observed in higher potential due to oxidation of guanine residuals in the Gquadruplex structure.