Investigation of Interaction of Small Natural Product Molecules and Human Telomeric G-Quadruplex and Thermal Stabilities of the Complexes by Electrospray Ionization Mass Spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the non-covalent interaction of human telomenc G-quadruplex (G4) DNA with 12 natural product molecules We found that Fangchinoline, a new ligand of the human telomenc G-quadruplex, had the highest binding affinity among these molecules The stabilities of the G-quadruplex and the complexes of the G-quadruplex with small molecules were investigated using a mass spectrometry heating experiment By Fangchinoline binding, the dissociation temperature (T-1/2) value of the complex of G-quadruplex with the ligand increased to 200 degrees C. We studied the binding mode and stability of the G-quadruplex with the small molecules using Autodock Possible binding sites were found and the binding energy was about -31 5 kJ mol Unlike the typical binding molecules with a planar structure. Fangchinoline is a new kind of G-quadruplex ligand and it gives us a different Insight for the design of new G-quadruplex ligands