Label-free simple fluorescence assay of DNA polymerase using the G-quadruplex structure

摘要

In this study, the G-quadruplex structure was used to detect the enzymatic activity and inhibition of the Klenow fragment exoa?’ (KFa?’) in the presence of N-methyl mesoporphyrin IX (NMM) which binds specifically to the G-quadruplex. We found that KFa?’ synthesized complementary strands of the template DNA, leading to a decrease in fluorescence intensity in the presence of NMM due to the difficulty in G-quadruplex formation. Thus, KFa?’ activity was sensitively detected using NMM. In addition, daidzein, the major phytoestrogen in soy, inhibited DNA synthesis mediated by KFa?’, and the half maximal inhibitory concentration (IC50) was determined to be 15.6 ??M by nonlinear regression analysis.