Fig. 8: Thermal stability of Mpro in the presence or absence of 5h.
Thermal stability of Mpro in the presence of GRL-1720 (a), 5h (b), and lopinavir (c) using differential scanning fluorimetry (DSF) was determined. Note in Experiment 1 that the Tm value of Mpro alone was 53.63 °C, while in the presence of 50 and 100 µM of GRL-1720, the values decreased to 49.39 and 47.95 °C, respectively, suggesting that the thermal stability of Mpro decreased when GRL-1720 bound to Mpro, suggesting that GRL-1720 formed covalent bond with Mpro. In experiment 2, the Tm value of Mpro alone was 51.17 °C, while in the presence of 50 and 100 µM of 5h, the values increased to 53.50 and 55.01 °C, respectively, suggesting that the thermal stability of Mpro increased when 5h bound to Mpro. When Mpro was treated with 50 and 100 µM lopinavir, decrement was seen with the Tm values with 48.64 and 48.87, suggesting that lopinavir non-specifically bound to Mpro (see the Results section). These data with the x-ray crystallographic analyses 5h strongly interacts with Mpro and potently inhibits its enzymatic activity as compared to GRL-1720. All the figures were generated with Microsoft Excel.
