Table 1.

Thermodynamic parameters of ligand binding

Protein	Ligand	Ka	Kd	T	ΔG0	ΔH	TΔS0	ΔCp	n
		×106m−1	μm	°C	kcal mol−1	kcal mol−1	kcal mol−1	cal mol−1 K−1
WT	Sop3	0.339 ± 0.003	2.95	15	−7.29	−23.3 ± 0.1	−16.0	−288 ± 43	0.909 ± 0.001
		0.174 ± 0.001	5.75	20	−7.03	−24.9 ± 0.1	−17.9		0.901 ± 0.002
		0.0883 ± 0.0007	11.3	25	−6.75	−25.0 ± 0.1	−18.3		0.866 ± 0.002
		0.0417 ± 0.0008	24.0	30	−6.40	−27.2 ± 0.3	−20.8		0.937 ± 0.009
		0.0193 ± 0.0007	51.8	35	−6.04	−29.3 ± 0.9	−23.3		0.870 ± 0.020
D193A		0.0201 ± 0.0005	49.8	25	−5.87	−24.8 ± 0.3	−18.9		0.946 ± 0.007
Q197A		0.00434 ± 0.00028	230	25	−4.96	−11.7 ± 0.3	−6.74		1.000a
WT	Sop4	1.72 ± 0.06	0.58	20	−8.36	−18.8 ± 0.1	−10.4	−295 ± 20	1.150 ± 0.002
		1.34 ± 0.06	0.75	25	−8.36	−20.2 ± 0.1	−11.8		1.150 ± 0.002
		0.822 ± 0.020	1.22	30	−8.20	−22.0 ± 0.1	−13.8		1.100 ± 0.002
		0.441 ± 0.009	2.27	35	−7.96	−23.1 ± 0.1	−15.1		1.080 ± 0.002
WT	Sop5	1.53 ± 0.07	0.65	15	−8.15	−14.4 ± 0.1	−6.25	−194 ± 22	1.390 ± 0.003
		1.21 ± 0.04	0.83	20	−8.16	−15.0 ± 0.1	−6.84		1.110 ± 0.002
		0.762 ± 0.020	1.31	25	−8.02	−16.0 ± 0.1	−7.98		1.130 ± 0.002
		0.442 ± 0.010	2.26	30	−7.83	−17.3 ± 0.1	−9.47		1.120 ± 0.002
		0.232 ± 0.006	4.31	35	−7.56	−16.6 ± 0.1	−9.04		1.210 ± 0.003
WT	β-1,2-Glucanb (average DP 25)	(0.00621 ± 0.00007)	(161)	25	(−5.17)	–c	–c		(0.867 ± 0.323)

^a Regression analysis was performed with the fixed n value because the low affinity of the mutant protein limited the protein concentration setting of the titration experiment, resulting in the low c value (=n × protein concentration × K_a <1).

^b The molar concentration was calculated based on the average DP.

^c Uninterpretable heat pulses made it difficult to determine accurate values.