Fig. 4.

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