Table 3.

Interaction parameters obtained from binding of RBD variants to ACE2 probed by ITC

RBD variant	Kd (nM)	N	ΔH (kcal/mol)	ΔG (kcal/mol)	−TΔS (kcal/mol)
Wildtype	10.0 ± 3.1	1.0 ± 0.0	−11.8 ± 0.2	−10.7 ± 0.2	1.0 ± 0.3
K417N	94.1 ± 9.5	0.9 ± 0.0	−11.7 ± 0.1	−9.4 ± 0.1	2.3 ± 0.1
Y453F	11.4 ± 1.7	1.0 ± 0.0	−11.8 ± 0.1	−10.7 ± 0.1	1.2 ± 0.1
S477N	5.0 ± 1.4	1.0 ± 0.0	−16.4 ± 0.2	−11.1 ± 0.2	5.3 ± 0.3
T478I	16.7 ± 5.6	1.0 ± 0.0	−11.8 ± 0.2	−10.4 ± 0.2	1.4 ± 0.3
E484K	51.5 ± 8.2	1.0 ± 0.0	−9.5 ± 0.2	−9.8 ± 0.1	−0.3 ± 0.2
S494P	13.8 ± 3.5	1.0 ± 0.0	−10.7 ± 0.2	−10.5 ± 0.1	0.2 ± 0.2
N501Y	3.0 ± 2.1	0.9 ± 0.0	−11.7 ± 0.2	−11.4 ± 0.4	0.2 ± 0.5
K417T/E484K/N501Y	1.6 ± 1.5	0.9 ± 0.0	−10.9 ± 0.2	−11.8 ± 0.5	−0.9 ± 0.6

Errors on ΔG and −TΔS were calculated using error propagation formulae (74).