S494 O-glycosylation site on the SARS-COV-2 RBD Affects the Virus Affinity to ACE2 and its Infectivity; A Molecular Dynamics Study

Rahnama, Shadi; Irani, Maryam Azimzadeh; Amininasab, Mehriar; Ejtehadi, Mohammad Reza

SARS-COV-2 is a strain of Coronavirus family which caused the extensive pandemic of COVID-19, which is still going on. Several studies showed that the glycosylation of virus spike (S) protein and the Angiotensin-Converting Enzyme 2 (ACE2) receptor on the host cell is critical for the virus infectivity. Molecular Dynamics (MD) simulations were used to explore the role of a novel mutated O-glycosylation site (D494S) on the Receptor Binding Domain (RBD) of S protein. This site was suggested as a key mediator of virus-host interaction. We showed that the decoration of S494 with elongated O-glycans results in stabilized interactions on the direct RBD-ACE2 interface with more favorable binding free energies for longer oligosaccharides. Hence, this crucial factor must be taken into account for any further inhibitory approaches towards RBD-ACE2 interaction.