Title
Investigation of the interactions between methylene blue and intramolecular G-quadruplexes: an explicit distinction in electrochemical behavior
Author
Ting Cao, Fangting Zhang, Liangyuan Cai, Yinglin Zhou, Niklaas J Buurma, Xinxiang Zhang
Year
2017
Journal
Analyst
Abstract
G-quadruplex sequences exist in eukaryotic organisms and prokaryotes, and the investigation of interactions between Gquadruplexes and small molecule ligands is important for gene therapy, biosensor fabrication, fluorescence imaging and so on. Here, we investigated the behaviour of methylene blue (MB), an electroactive molecule, in the presence of different intramolecular G-quadruplexes by electrochemical method using a miniaturized electrochemical device based on its intrinsic electrochemical property. Although the effects of MB on different intramolecular G-quadruplex structures are not obvious by circular dichroism spectroscopy, distinct differences in binding affinities of MB with different intramolecular Gquadruplexes were fast and easily observed by the electrochemical technique. At the same time, for the human telomerase G-rich sequence (HT), the diffusion current of MB changed sensitively under different ion conditions due to the formation of different conformations of HT, which indicated that our electrochemical method has the potential to study the influence of metal ions on the conformations of the G-quadruplexes with simplicity, rapid response and low cost. From all these, new stacking mechanism and rule were obtained, which were also validated by docking studies and isothermal titration calorimetry (ITC).
Instrument
J-815
Keywords
Circular dichroism, DNA structure, Ligand binding, Biochemistry