Fig. 2.

The changes in enthalpy of the SARS-CoV-2/ACE2 host cell system on the association. H1 represents the total reacting amino acids bond energy by adding RBD amino acid binding energies (E1) to ACE2 amino acid binding energies (E2). H2 represents the total reacted amino acids bond energy by adding binding energy of each RBD amino acid to ACE2 amino acid (e1 + e2 + … = Ʃe). Negative values of ΔH indicate the higher potential binding energy level of reacting amino acids (H1 > H2)