. 2020 Jun 23;5(26):16292–16298. doi: 10.1021/acsomega.0c02125

Table 3. Various Components of the Gibbs Free Energy of Binding Calculated by Implicit Solvation and Adaptive-Basis Poisson–Boltzmann Solver (APBS)^a.

protein systems	Coulombic interaction free energy Δ_CoulG	corrected solvation free energy difference ΔΔ_solvG_corr	Gibbs free energy of binding Δ_bindG°
CoV^ox···ACE2^ox	–564.5	557.2	–7.3^b
CoV^red···ACE2^ox	–673.0	661.8	–11.2
CoV^ox···ACE2^red	–696.6	693.1	–3.4
CoV^red···ACE2^red	–528.4	580.4	52.0
CoV-2^ox···ACE2^ox	–659.6	648.2	–10.4^c
CoV-2^red···ACE2^ox	–638.2	632.2	–6.0
CoV-2^ox···ACE2^red	–531.9	528.1	–3.8
CoV-2^red···ACE2^red	–655.3	712.6	57.3

All energies are expressed in kcal/mol. An estimated uncertainty of 1–3 kcal/mol was determined for the computed Gibbs free energy.

An experimental value of −10.3 kcal/mol was obtained for SARS-CoV by Lan et al.³⁴

An experimental K_d value of −10.4 kcal/mol for SARS-CoV-2···ACE2 complex, reported by Wang et al.,¹⁵ was used as correction in eq 3.

Table 3. Various Components of the Gibbs Free Energy of Binding Calculated by Implicit Solvation and Adaptive-Basis Poisson–Boltzmann Solver (APBS)a.