Recently, Ji et al. demonstrated that the receptor binding domain of SARS-CoV-2 was capable of binding ACE2 in the context of the SARS-CoV spike protein [51]. Among SRAS-CoV spike protein’s fourteen residues predicted to interact directly with human ACE2 as the receptor for SARS-CoV, eight amino acids are well conserved in homology SARS-CoV-2 spike protein [26,102]. At the same time, Wan et al. showed that SARS-CoV-2 uses ACE2 receptors to infect humans, bats, civets, monkeys, and swine, but not mice [106]. Compared to previously reported SARS-CoV strains, SARS-CoV-2 uses ACE2 receptors more efficiently than human SARS-CoV (year 2003), but less efficiently than human SARS-CoV (year 2002) [106]. The mutation of proteins determines two important characteristics of the SARS-CoV-2: A higher ability to infect and enhanced pathogenicity than the bat-like SARS-CoV, but a lower pathogenicity than SARS-CoV [43].