Effect of the N501Y Mutation on Ligands Complexed with SARS-CoV-2 RBD: Insights on Potential Drug Candidates for COVID-19

Bioactive compounds against SARS-CoV-2 targets could be potential treatments for COVID-19. Inhibitors of the receptor-binding domain (RBD) on the viral spike protein can block its binding to the human angiotensin-converting enzyme type II (ACE2) receptor. This study presents ligands based on natural products and synthetic compounds, targeting multiple N501/Y501 RBDs, besides RBD-ACE2, over different regions. The selected compounds were evaluated by docking using consensus scoring, pharmacokinetics/toxicological analyses, and molecular dynamics. Additionally, N501/Y501 RBD-ACE2 interaction properties and RBD–ligand complexes were compared. We identified that coenzyme Q10, 1-stearoyl-2-arachidonoylglycerol, and palmitone showed the greatest RBD interactions. Targeting specific residues (in particular, tyrosine) in the C-, N-terminal, and central RBD sites promoted more stable protein–ligand interactions than in the N-terminal region only. Our results indicate that the molecules had more energetically favorable interactions with residues from distinct RBD regions rather than only interacting with residues in the N-terminal site. Moreover, the compounds might better interact with mutated N501Y than N501 RBDs. These hits can be optimized to leads and investigated through QSAR models and biological assays to comprehend mechanisms better. Altogether, such strategies may anticipate antiviral strategies if or when future variants and other CoVs arise.