Fig. 2 Thermal shifts (ΔTm) of SARS-CoV nsp14 in the absence or presence of SAM, sinefungin and 9 dinucleoside inhibitors 6 and 9–16. Thermal stability of SARS-CoV nsp14 upon ligand binding was monitored by differential scanning fluorimetry. Assays were carried out in reaction mixture [20 mM HEPES (pH 7.5), 150 mM NaCl, 1x SYPRO orange dye] in the presence of 5 μM SARS-CoV nsp14 protein and 1 mM compound previously dissolved in 100% DMSO. The bars and error bars correspond to the mean values from three independent measurements and their s.d.’s, respectively.