Table 2. Temperature dependence of... | Rockefeller University Press

Table 2.

Temperature dependence of substrate binding

Titrant	Titrand (cell)		T (°C)	Test number	K_d (mM)	Free energy change (ΔG; kJ/mol)	P	ΔH (kJ/mol)	Entropy change (−TΔS; kJ/mol)	ΔC_p (J/mol·K)
Mel	MelB_St	/	15	2	9.15 ± 1.06^a	−11.27 ± 0.27	>0.05^b	−25.91 ± 4.58	14.64 ± 4.30	+ 643.01 ± 26.92
			20	2	9.59 ± 1.01	−11.34 ± 0.26		−23.26 ± 5.23	11.92 ± 4.97
			25	2	10.82 ± 2.49	−11.29 ± 0.58		−19.64 ± 6.13	8.35 ± 6.71
			30	2	13.79 ± 1.18	−10.81 ± 0.22		−16.40 ± 5.45	5.59 ± 5.66
Na⁺	MelB_St	/	15	2	0.51 ± 0.08	-18.18 ± 0.39	>0.05	−35.75 ± 0.90	17.56 ± 1.30	+1,305.20 ± 50.63
			20	2	0.60 ± 0.10	−18.13 ± 0.49		−28.20 ± 0.43	10.06 ± 0.02
			25	2	0.59 ± 0.12	−18.46 ± 0.42		−22.11 ± 0.80	3.65 ± 0.31
			30	2	0.79 ± 0.07	−18.00 ± 0.22		−16.02 ± 1.40	−1.98 ± 1.62
Mel	MelB_St	Na⁺	15	3	1.05 ± 0.01	−16.43 ± 0.03	>0.05	−6.46 ± 0.43	−9.61 ± 0.67	− 424.93 ± 40.78
			20	3	0.95 ± 0.13	−17.09 ± 0.40		−9.72 ± 0.59	−7.37 ± 0.99
			25	5	1.18 ± 0.01	−16.71 ± 0.03		−11.97 ± 0.23	−4.75 ± 0.26
			30	3	1.41 ± 0.04	−16.55 ± 0.07		−13.57 ± 0.24	−2.98 ± 0.31
			35	2	1.78 ± 0.14	−16.23 ± 0.20		−15.16 ± 0.44	−1.09 ± 0.23
Na⁺	MelB_St	Mel	15	2	0.06 ± 0.01	−23.29 ± 0.20	>0.05	−10.70 ± 0.06	−12.59 ± 0.26	−760.50 ± 33.18
			20	2	0.07 ± 0.01	-23.24 ± 0.17		−15.14 ± 0.15	−8.11 ± 0.03
			25	2	0.12 ± 0.04	−22.55 ± 0.82		−18.74 ± 0.80	−3.82 ± 0.03
			30	2	0.12 ± 0.03	−22.95 ± 0.74		−22.17 ± 0.52	0.78 ± 1.26

Titrant	Titrand (cell)		T (°C)	Test number	K_d (mM)	Free energy change (ΔG; kJ/mol)	P	ΔH (kJ/mol)	Entropy change (−TΔS; kJ/mol)	ΔC_p (J/mol·K)
Mel	MelB_St	/	15	2	9.15 ± 1.06^a	−11.27 ± 0.27	>0.05^b	−25.91 ± 4.58	14.64 ± 4.30	+ 643.01 ± 26.92
			20	2	9.59 ± 1.01	−11.34 ± 0.26		−23.26 ± 5.23	11.92 ± 4.97
			25	2	10.82 ± 2.49	−11.29 ± 0.58		−19.64 ± 6.13	8.35 ± 6.71
			30	2	13.79 ± 1.18	−10.81 ± 0.22		−16.40 ± 5.45	5.59 ± 5.66
Na⁺	MelB_St	/	15	2	0.51 ± 0.08	-18.18 ± 0.39	>0.05	−35.75 ± 0.90	17.56 ± 1.30	+1,305.20 ± 50.63
			20	2	0.60 ± 0.10	−18.13 ± 0.49		−28.20 ± 0.43	10.06 ± 0.02
			25	2	0.59 ± 0.12	−18.46 ± 0.42		−22.11 ± 0.80	3.65 ± 0.31
			30	2	0.79 ± 0.07	−18.00 ± 0.22		−16.02 ± 1.40	−1.98 ± 1.62
Mel	MelB_St	Na⁺	15	3	1.05 ± 0.01	−16.43 ± 0.03	>0.05	−6.46 ± 0.43	−9.61 ± 0.67	− 424.93 ± 40.78
			20	3	0.95 ± 0.13	−17.09 ± 0.40		−9.72 ± 0.59	−7.37 ± 0.99
			25	5	1.18 ± 0.01	−16.71 ± 0.03		−11.97 ± 0.23	−4.75 ± 0.26
			30	3	1.41 ± 0.04	−16.55 ± 0.07		−13.57 ± 0.24	−2.98 ± 0.31
			35	2	1.78 ± 0.14	−16.23 ± 0.20		−15.16 ± 0.44	−1.09 ± 0.23
Na⁺	MelB_St	Mel	15	2	0.06 ± 0.01	−23.29 ± 0.20	>0.05	−10.70 ± 0.06	−12.59 ± 0.26	−760.50 ± 33.18
			20	2	0.07 ± 0.01	-23.24 ± 0.17		−15.14 ± 0.15	−8.11 ± 0.03
			25	2	0.12 ± 0.04	−22.55 ± 0.82		−18.74 ± 0.80	−3.82 ± 0.03
			30	2	0.12 ± 0.03	−22.95 ± 0.74		−22.17 ± 0.52	0.78 ± 1.26

SEM.

Within each temperature set, the smallest and largest number were used for unpaired t test (P > 0.05, no statistical significance among the temperatures).