FIGURE 9.

Hypothetical placement of compound 45 in the active site of SARS‐CoV PLpro enzyme (PDB code 3MJ5). As shown, if the placement of compound 45 in the active site of the PLpro is similar to compound 43 in terms of spatial orientation (which is very likely), the α, β unsaturated ketone functional group will be placed in a suitable orientation and distance to create Michael interaction with Cys271 (graphic image was prepared by Discovery Studio Visualizer v4.5., and distance was calculated by Molegro Molecular Viewer 6.5 software)