SARS-CoV-2 virus is the serious health concern throughout the world. A comprehensive investigation of binding of SARS-CoV-2 active site with host receptor protein hACE2 is important in designing effective drugs. In the present work, the major amino acid binding partners between the virus CTD and host receptor have been studied and are compared with SARS-CoV RBD binding with hACE2. Our investigation show that some unique hydrogen bond pairs which were not reported in previous work. Along with hydrogen bonding, salt-bridges, hydrophobic interactions and contributions of electrostatic and van der Waals contacts play significant role in binding mechanism. The binding affinity of SARS-CoV-2 CTD/hACE2 is greater than SARS-CoV RBD/hACE2. This outcome is also verified from the free energy estimation by using umbrella sampling.

SARS-CoV-2 病毒是全世界严重的健康问题。SARS-CoV-2活性位点与宿主受体蛋白hACE2结合的综合研究对于设计有效药物很重要。在目前的工作中，已经研究了病毒 CTD 和宿主受体之间的主要氨基酸结合伙伴，并将其与 SARS-CoV RBD 与 hACE2 的结合进行了比较。我们的调查表明，一些独特的氢键对在以前的工作中没有报道过。除了氢键之外，盐桥、疏水相互作用以及静电和范德华接触的贡献在结合机制中也起着重要作用。SARS-CoV-2 CTD/hACE2 的结合亲和力大于 SARS-CoV RBD/hACE2。该结果也通过使用伞状采样从自由能估计中得到验证。