Extended Data Fig. 5. Overlay of the four crystal structures of 3CL.

Crystal structure of 3CL in apo form (gray), in complex with, compound 4 (green for 3CL and magenta for compound 4), GC376 (cyan for 3CL and yellow for GC376), and MAC-5576 (orange for 3CL and purple for MAC-5576 fragment). One protomer for each structure is shown, with the inhibitors shown with stick models. The terminal residue of each structure, as well as two stretches of residues near the binding site that exhibit local conformational change between the apo and inhibitor-bound structures are labeled.