Table 2.

Thermodynamic parameters of wild-type and mutant SdCen variants binding to XPC and Sfi1.

Protein C-SdCen	Ligand	Ca2+	N	Ka (error) (106 M−1)	ΔH (error) (kcal/mol)	TΔS (kcal/mol)	ΔG (kcal/mol)
WT	P17-XPC 30 °C	+	0.95	59.4(9.10)	−23.4(0.16)	−12.63	−10.77
	30 °C	−	1.02	30.2 (1.2)	−33.8 (0.07)	−23.39	−10.41
	37 °C	+	1.02	73.2(7.0)	−23.36(0.08)	−12.18	−11.18
	37 °C	−	1.04	10.6 (0.4)	−40.6 (0.12)	−29.94	−10.66
F109L	P17-XPC 30 °C	+	1.02	67.1(5.0)	−15.63(0.09)	−4.78	−10.85
	30 °C	−	1.33	2.02 (0.07)	−20.6 (0.09)	−11.88	−8.72
	37 °C	+	1.23	37.8(5.02)	−16.97(0.10)	−6.20	−10.77
	37 °C	−	1.05	0.62 (0.01)	−28.96 (0.2)	−20.27	−8.63
E144A	P17-XPC 30 °C	+	1.02	95.6(15.6)	−20.44(0.12)	−9.36	−11.08
	30 °C	−	1.15	10.1 (0.5)	−29.5 (0.13)	−19.78	−9.72
	37 °C	+	1.01	107(11.5)	−25.17(0.62)	−13.76	−11.41
	37 °C	−	1.03	2.49 (0.08)	−38.4 (0.17)	−28.66	−9.74
F109L-E144A	P17-XPC 30 °C	+	1.07	32.7(2.65)	−14.11(0.06)	−3.69	−10.42
	30 °C	−	1.0	0.43 (0.01)	−22.2 (0.2)	−14.39	−7.81
	37 °C	+	1.01	29(1.92)	−17.19(0.06)	−6.60	−10.59
	37 °C	−	1.06	0.24 (1.24)	−21.2 (0.5)	−13.21	−7.99
WT	R18-Sfi1 30 °C	−	1.12	4.5 (0.1)	−31.5 (0.08)	−22.24	−9.26
	37 °C	−	1.15	1.23 (0.02)	−37.09 (0.1)	−27.78	−9.31
F109L	R18-Sfi1 30 °C	−	1.17	0.77 (0.01)	−23.2 (0.1)	−14.96	−8.24
	37 °C	−	1.05	0.23 (0.01)	−30.4 (1.0)	−22.3	−8.10
E144A	R18-Sfi1 30 °C	−	1.19	4.64 (0.08)	−30.3 (0.06)	−21.06	−9.25
	37 °C	−	1.12	1.38 (0.04)	−36.2 (0.17)	−26.88	−9.34
F109L-E144A	R18-Sfi1 30 °C	−	1.17	0.66 (0.02)	−24.4 (0.16)	−16.33	−8.07
	37 °C	−	1.04	0.29 (0.01)	−26.4 (0.3)	−18.24	−8.19

The ITC experiments were conducted at 30 °C or 37 °C in buffer (MOPS 50 mM, NaCl 100 mM, EDTA 2 mM or Ca²⁺ 2 mM pH 7.5). N was the stoichiometry of binding. NB means no binding. The standard deviations of the fitted parameters are given in parenthesis.