TABLE 3.

Thermodynamic stability of mPrP(23–231) wild type and variants at pH 7 and 4 (22°C) at different ionic strengths

	ΔG° (kJ/mol)	ΔΔG° (kJ/mol)	Cooperativity of folding (kJ/mol M)	[urea]1/2 (M)
pH = 4.0
Ionic strength = 30 mM
[NaCl] = 0
Wild type	−17.3 ± 0.6		4.9 ± 0.2	3.53
E200K	−16.4 ± 0.6	0.9 ± 1.2	5.2 ± 0.2	3.15
F198S	−9.5 ± 0.2	7.8 ± 0.8	3.8 ± 0.1	2.50
D178N	−9.4 ± 0.2	7.9 ± 0.8	4.0 ± 0.1	2.35
pH = 7.0
Ionic strength = 80 mM
[NaCl] = 0
Wild type	−25.6 ± 1.6		4.2 ± 0.3	6.09
E200K	−25.3 ± 1.7	0.3 ± 3.3	4.4 ± 0.3	5.75
F198S	*
D178N	*
pH = 7.0
Ionic strength = 215 mM
[NaCl] = 135 mM
Wild type	−26.4 ± 1.7		4.4 ± 0.3	6.00
E200K	−27.4 ± 1.5	−1 ± 3.2	4.9 ± 0.3	5.59
F198S	*
D178N	*

^*Could not be evaluated quantitatively due to partial aggregation during the transition.