Activities of pyrazolopyrimidine sulfamates in selected biochemical assays.

ATP consumption by PfTyrRS (25 nM) in the presence of ATP (10 μM), tyrosine (200 μM), pyrophosphatase (1 unit/mL) and cognate tRNATyr (4.8 μM), was measured using the Kinase Glo assay after incubation at 37°C for 1 h. The Tm values for PfTyrRS and HsTyrRS (2.3 μM) were measured in the apo form or after incubation at 37°C for 2 h (PfTyrRS) or 4 h (HsTyrRS) with the nucleoside sulfamates (50 μM with PfTyrRS and 200 μM with HsTyrRS) in the presence of 10 μM ATP, 20 μM tyrosine, 4 μM cognate tRNATyr (PfTyrRS) or 8 mg/mL yeast tRNA (HsTyrRS). *KD values (apparent) are estimated from differential scanning fluorimetry (DSF) analysis using an irreversible protein thermal unfolding model that has been described previously [59]. Data values represent mean ± SEM. AMS = Adenosine 5’-sulfamate. n = Number of biological repeats.