Fig 4. Dose response inhibition of the N7 and 2’-O methylation activities of the WNV MTase by the most potent compound NSC 306711.

(A) TLC analyses of the N7 and 2’-O inhibition of the WNV MTase by NSC 306711. The migration positions of the G*pppA and m⁷G*pppA molecules are labeled on the side of the TLC images. The specific activity (%) for N7 = Intensity (m⁷G*pppA)/(Intensity (G*pppA)+Intensity (m⁷G*pppA)) *100). The specific activity (%) for 2’-O = Intensity (m⁷G*pppAm)/(Intensity (m⁷G*pppA)+Intensity (m⁷G*pppAm)) *100). The relative methylation activity without compounds was set at 100%, and the relative methylation activity with a particular compound was defined as specific activity (compound)/specific activity (no compound) * 100. (B-C) Curve fitting to determine the IC₅₀ values for each compound on the N7 (B) and 2’-O (C) MTase activities of the WNV MTase. The IC₅₀ value was determined by fitting of the dose–response curve as described in methods section. Each reaction was carried out in triplicate and the standard deviation is plotted.