Studies On Supramolecular Chemistry Related To G-quadruplex DNA Based On ESI-HRMS

G-quadruplex is a special secondary structure of DNA formed by G-rich DNA sequences. G-quadruplex play an important role in the carcinogenesis. Targeting the G-quadruplex to identify drugs has been a hot issue. As with the fasting developing of artificial DNA, G-quadruplex as one of functional nucleic acids(FNAs) attracts a lot of attention. G-quadruplex can be used to analyze and detect metal ions, smallmolecule drug, proteins and even DNA. Electrosparay ionization(ESI-HRMS), as a soft ionization technology, is an important way to study biomacromolecule such as proteins, DNA.The paper studied the supramolecular chemistry related to G-quadruplex DNA by ESI-HRMS. The following work was carried out in this paper:Firstly, the conditions of ESI-HRMS for detection of G-rich DNA, G-rich DNA + K+, G-rich DNA + K+ + Berberine were studied. The mass spectrum conditions, which included reaction time, gas tempreture, voltage of Fragmentor, were optimized and determined. And then the effect of buffer pH was also investigated and determined.Secondly, the interactions of G-rich DNAs(PS2.M, PW17) with various concentrations of Na+, K+ and Pb2+ were studied. The possible G-quadruplex structures were indentified by deconvolution of the raw data of HRMS. We found the compositions of the G-quadruplex complex were changed with different concentration of mental ions. The binding constants of metal ion to G-rich DNAs were calculated.Thirdly, the interaction between small ligand(Berberine) and G-quadruplex DNA containing different mental ion were investigated. The compositions of complex of Berberine with G-quadruplex were indentifide by the deconvolution MS data. We also found the compositions of the G-quadruplex-mental ion-Berberine complex were changed with the variation of Berberine’s concentration. The possible formation mechanism of G-quadruplex were discussed based on the the experimental data.