Fig. 3.

Docked poses of compound 4d (stick figure) with SARS-CoV-2 (COVID-19) main protease (PDB ID: 6XFN) (A) Protein backbone-ligand interactions; (B) Docked pose of ligand 4d (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 4d with 6XFN (hydrophobicity surface) at the active binding site; (D) 2D view of interaction type of ligand 4d 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.)