Binding Mechanism of SARS-CoV(-2) into hACE2 Receptor

We have investigated the entry pathways and energy variation during the interaction of SARS-CoV(-2) and hACE2 receptor protein. Classical molecular dynamics (MD) simulation has been carried out for the purpose. In this study, three important binding regions between SARS-CoV(-2) and hACE2 have been detected. The binding is supported by several interactions like hydrogen bonding, salt bridges, hydrophobic interactions, electrostatics and van der Waals. The outcomes of MD simulations are analysed by estimating free energy change taking displacement of virus molecule from human protein receptor as the reaction coordinates. The binding free energy differences (~1.9 kcal/mol) of SARS-CoV and SARS-CoV-2 to hACE2 receptor explains why SARS-CoV-2 is more severe than SARS-CoV. Further to understand the strengths of different forms of the SARS-COV-2 virus we have studied the binding free energy of its different variants like beta and gamma.