Table 1.

Computed relative free energies of binding due to single-site mutations from the receptor ACE2–RBD and the antibody 80R–RBD complexes of SARS-CoV to the corresponding residues in SARS-CoV-2

Mutation	ΔΔG, kcal/mol
SARS-CoV:ACE2
Y484→Q498	−0.2 ± 0.6
L472→F486	−1.2 ± 0.2
D480→S494, K439→L452	−1.9 ± 0.8
T487→N501	−0.5 ± 0.3
N479→Q493	−0.8 ± 0.2
V404→K417, K447→N460*	−2.2 ± 0.9
SARS-CoV:80R
Y484→Q498	−0.2 ± 0.4
L472→F486	−1.4 ± 0.2
D480→S494, K439→L452	3.6 ± 0.5

^*Double mutation was performed to keep the system neutral in free energy simulations. Here, K447 is solvent-exposed both in the monomer and in the complex distant from the binding interface and the mutation K447→N460 is expected to cancel out to make minimal contribution to the computed binding free energy.