Comparison of Binding Site of Remdesivir and Its Metabolites with NSP12-NSP7-NSP8, and NSP3 of SARS CoV-2 Virus and Alternative Potential Drugs for COVID-19 Treatment.

Remdesivir was approved by the U.S.A. Food and Drug administration for emergency use to interfere with the replication of SARS CoV-2 virus (the agent that causes COVID-19) in adults and children hospitalized with severe disease. The crystal structure of the metabolite of remdesivir (Monophosphate of GS-441524) and NSP12-NSP8-NSP7 of SARS CoV-2 virus was recently reported. The crystal structures of ADP-Ribose or AMP and NSP3 of SARS CoV-2 virus were also released, recently. This study compared their binding sites and suggests the crystal structure of NSP3 of SARS CoV-2 virus as an alternative binding site of AMP or ADP-ribose to treat COVID-19. We virtually screened 682 FDA-approved compounds, and the top 10 compounds were selected by analysis of docking scores, (G-score, D-score, and Chemscore) and visual analysis using a structure-based docking approach of NSP3 of SARS CoV-2 virus. All immunization approaches are based on the SARS-CoV-2 virus spike protein. A recent study reported that the D614G mutation in the SARS-CoV-2 virus spike protein reduces S1 shedding and increases infectivity of SARS COV-2 virus. Therefore, if there is a severe change in the spike protein of a modified Coronavirus, all developed vaccines can lose their efficacy, necessitating the need for an alternative treatment method. The top 10 compounds (FDA-approved) in this study are selected based on NSP 3 binding site, and therefore are a potential viable treatment because they will show potential activity for all mutations in the SARS-CoV-2 virus spike protein.