Table 3.

Binding affinity of intact ACE2 and tACE2 for S protein and their dissociation constant (K_d) at different temperatures.

#	Temperature	Binding affinity ΔG (kcal mol-1)		Dissociation constant Kd (M)
		ACE2	tACE2	ACE2	tACE2
1	20˚C	−10.7	−12.7	1.0 × 10−8	3.2 × 10−10
2	24˚C	−10.7	−12.7	1.3 × 10−8	4.2 × 10−10
3	28˚C	−10.7	−12.7	1.6 × 10−8	5.6 × 10−10
4	32˚C	−10.7	−12.7	2.1× 10−8	7.5 × 10−10
5	36˚C	−10.7	−12.7	2.6 × 10−8	9.8 × 10−10
6	37˚C	−10.7	−12.7	2.7 × 10−8	1.0 × 10−9