FIGURE 1.

Enzymatic activities of the Gly-11 → Ala mutant and wild-type SARS-CoV 3CL^pro. The fluorogenic substrate at a concentration of 10 μm was incubated with 1 μm Gly-11 → Ala mutant or wild-type SARS-CoV 3CL^pro in 10 mm Tris-HCl, pH 7.5, 100 mm NaCl, 5 mm DTT, 1 mm EDTA, at 25 °C. Increase of emission fluorescence intensity at 488 nm wavelength was recorded at 10-min intervals, λ_EX = 340 nm. The emission spectrum was recorded for 90 min, and the activity of wild-type SARS 3CL^pro was taken as 100%.