Approach to the mechanism of action of hydroxychloroquine on SARS-CoV-2: a molecular docking study.

We aimed to analyze the interactions of both hydroxychloroquine and chloroquine with SARS-CoV-2 and identify their possible role for the prevention/treatment of COVID-19 by molecular docking studies. Protein crystal structures of SARS-CoV-2 and ACE2, the compounds hydroxychloroquine and chloroquine, and other ligand structures were minimized by OPLS3 force field. Glide Standard Precision and Extra Precision docking are performed and MM-GBSA values ​​are calculated. Molecular docking studies showed that hydroxychloroquine and chloroquine do not interact with SARS-CoV-2 proteins, but bind to the amino acids ASP350, ASP382, ALA348, PHE40 and PHE390 on the ACE2 allosteric site rather than the ACE2 active site. Our results showed that neither hydroxychloroquine and chloroquine bind to the active site of ACE2. However, both molecules prevent the binding of SARS-CoV-2 spike protein to ACE2 by interacting with the allosteric site. This result can help ACE2 inhibitor drug development studies to prevent viruses entering the cell by attaching spike protein to ACE2. Communicated by Ramaswamy H. Sarma.