Figure 1. Inhibition of BLM helicase unwinding activity.
(A, left) Chemical drawings for compounds 1, 2, and ML216. (A, right) Dose response curves from fluorescence-based DNA unwinding assays with BLM-HD. Experimental data were fitted with a four parameter, log(inhibitor) vs. response model with variable slope. Calculated values for IC50, Hill slope (nH) and 95% confidence intervals (95% CI) are given in each case. (B) Turnover of ATP by BLM-HD, as measured by a malachite-green end-point assay, is strongly stimulated in the presence of a 20-base single-stranded oligonucleotide. (C) Dose response curves from ATP-turnover assays with BLM-HD. Data were fitted as for (A). In each case data points are the mean of three technical replicates, with error bars representing one standard deviation (1 SD).
Figure 1—figure supplement 1. Assay data for compunds 3 to 7.
(Top) Chemical drawings for compounds 3 to 7. (Middle) Dose response curves from fluorescence-based DNA unwinding assays with BLM-HD. Data points are the mean of three technical replicates with error bars representing 1 SD. (Bottom) Dose response curves from ATP turnover assays with BLM-HD. Data points represent the mean from at least two individual experiments, each containing three technical replicates. Error bars represent the standard error of the mean (SEM). Experimental data were fitted with a four parameter, log(inhibitor) vs. response model with variable slope. Calculated values for IC50, Hill slope (nH) and 95% confidence intervals (95% CI) are reported in Table 1. Data points excluded from fitting are coloured red.
Figure 1—figure supplement 2. Indicative binding isotherms for titrations of Mg-ADP and Mg-ATPγS into BLM-HD as measured by MST.
Fitted lines are intended as visual aids only, as the data only represent values from a single preliminary experiment.