Label-free fluorescence turn-on detection of uracil DNA glycosylase activity based on G-quadruplex formation

•A novel, label-free fluorescence assay has been developed for the detection of uracil DNA glycosylase (UDG) activity.•This method is highly selective and sensitive with a 0.01 U/mL limit of detection.•Because no labeling was required, the method is simple and cost-effective.•The inhibition effect of 5-fluorouracil towards UDG activity was evaluated.

We have developed a new methodology for fluorescence turn-on detection of uracil DNA glycosylase (UDG) activity based on G-quadruplex formation using a thioflavin T probe. In the presence of UDG, it catalyzed the hydrolysis of the uracil bases in the duplex DNA, resulting in the dissociation of the duplex DNA owing to their low melting temperature. Then, the probe DNA can be recognized quickly by the ThT dye and resulting in an increase in fluorescence. This approach is highly selective and sensitive with a detection limit of 0.01 U/mL. It is simple and cost effective without requirement of labeling with a fluorophore-quencher pair. This new method could be used to evaluate the inhibition effect of 5-fluorouracil on UDG activity, and become a useful tool in biomedical research.

Graphical abstractA label-free fluorescence assay for the detection of UDG activity with high sensitivity and selectivity was established based on G-quadruplex formation.Figure optionsDownload full-size imageDownload as PowerPoint slide