Fig. 1. Structure of M^pro and density maps of ebselen binding.

(A) M^pro dimer and (B) protomer A (top view). In both panels, M^pro domains I, II, and III are shown in red, blue, and gray, respectively. Cys¹⁴⁵ and His⁴¹ (the catalytic dyad) are shown in cyan. Yellow surfaces show the most probable interaction sites between M^pro and ebselen (highest probability density). The loop (residues 185 to 201) connecting domains I and II with domain III is shown in pink (B). The inset shows the chemical structure of the ebselen molecule.