Fig. 1.

Docked poses of compound 5a (stick figure) with COVID-19 main protease (PDB ID: 6LZE) (A) Protein backbone-ligand interactions; (B) Docked pose of ligand 5a (colour code for ligand: Black-C: White-H; Red-O; Blue-N) conventional hydrogen bonding interactions shown as dashed lines (Green) with 6LZE; (C) Lingard 5a with 6LZE (hydrophobicity surface) at the active binding site; (D) 2D view of interaction type of ligand 5a with surrounding amino acids of 6LZE. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)