Fig. 3. TRES-based screening method could effectively avoid false negatives. (A and B) G-quadruplex/1 method in steady-state emission mode or TRES mode in the presence of 100 U mL⁻¹ UDG, 100 U mL⁻¹ UDG + 100 U mL⁻¹ UDGI, or 100 U mL⁻¹ UDG + 10 μM A8. Luminescence emission intensity was recorded at 450–700 nm with excitation at 355 nm. (C) Dose effect of A8 on UDG activity as measured by TRES. (D) Dose effect of S13 on UDG activity as measured by TRES. Error bars represent the standard deviations of the results from three independent experiments. P values were calculated using a two-sided t-test. *P < 0.05, **P < 0.01 vs. UDG group, respectively.