Specific Recognition of Human Telomeric G-Quadruplex DNA with Small Molecules and the Conformational analysis by ESI Mass Spectrometry and Circular Dichroism Spectropolarimetry

摘要

Electrospray ionization mass spectrometry(ESI-MS)was utilized to investigate the binding affinity and sto-ichiometry of small molecules with human telomeric G-quadruplex DNA.The binding-affinity order obtained for the(AGGGTT)4 quadruplex was:Te101 > ImImIm beta Dp PyPyPy gamma ImIm-Im beta Dp.The specific binding of TelOl'and PyPyPy gamma ImImIm beta Dp in one system consisting of human telomeric G-quadruplex and duplex DNA was observed directly for the first time.This revealed that PyPyPy gamma ImImIm beta Dp has a binding specificity for the duplex DNA,whereas TelOl selectively recognizes the G-quadruplex DNA.Moreover,both ESI-MS and circular dichroism(CD)spectra indicated that TelOl favored the formation and stabilization of the antiparallel G-quadruplex,and a structural transition of the(AGGGTT)4 sequence from a coexistence of parallel and antiparallel G-quadruplexes to a parallel G-quadruplex induced by annealing.