Digging for the Discovery of SARS-CoV-2 nsp12 Inhibitors: A Pharmacophore-Based and Molecular Dynamics Simulation Study
Abstract Background: The severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) is a grave global threat causing Coronavirus Disease 2019 (COVID-19). The therapeutics are urgently needed to cure patients severely infected with COVID-19. The aim of the study was to investigate for potential candidates of nsp12 inhibitors by searching for druggable cavity pockets within the viral protein and drug discovery.Methods: The crystallographic structure of SARS-CoV-2 nsp12 was searched for strong druggable cavity pockets and pharmacophore features by the CavityPlus server. The features were selected for high-throughput screening (HTS) of a chemical library of ZINC natural products and hit identification database by ZINCPharmer. Autodock Vina was furthered utilized for estimation of hits' affinities to nsp12. A lead compound with the highest affinity to nsp12 was simulated dynamically by GROMACS for 10 nanoseconds (ns) to measure the hit stability in complex with nsp12 and conformational changes.Results: 1 of 6 cavities with the highest score was selected for extraction of pharmacophore features and hit-identification. 9 pharmacophores were screened, and a total of unique 1274 hits were identified. One compound, ZINV03977803, with an -11.0 Kcal.mol-1 affinity was selected as the lead compound for molecular dynamic simulation (MDS). The results showed stable interaction between ZINV03977803 and nsp12 during 10 ns of simulation. The room-mean-square of deviation (RMSD) measure showed dramatically high conformational changes in the complex of ZINV03977803 and nsp12 compare two the viral proteins alone.Conclusions: The lead compound ZINV03977803 showed stable interaction with higher potential and hydrogen bonding with the catalytic subunit of SARS-CoV-2, nsp12. It could also inhibit the SARS-CoV-2 life cycle by direct interaction with nsp12 and inhibits RdRp complex formation.