Table 1.

Φ value for the folding of PDZ2

Mutant	ΔΔGD—N	ΦTS1*	ΦTS1†	ΦTS2†
V16A	2.14 ± 0.12	0.27 ± 0.04	0.23 ± 0.02	0.62 ± 0.05
L18A	3.52 ± 0.14	0.22 ± 0.03	0.09 ± 0.01	0.37 ± 0.01
T21S	0.05 ± 0.09	—‡	—‡	—‡
L25A	2.41 ± 0.12	0.13 ± 0.04	0.18 ± 0.15	0.33 ± 0.11
I27V	1.58 ± 0.13	0.24 ± 0.06	0.15 ± 0.03	0.43 ± 0.04
V29A	3.23 ± 0.15	0.09 ± 0.02	0.10 ± 0.09	0.44 ± 0.12
T30S	0.23 ± 0.08	—‡	—‡	—‡
V33A	−0.21 ± 0.06	—‡	—‡	—‡
V33G	0.1 ± 0.07	—‡	—‡	—‡
T35S	0.1 ± 0.09	—‡	—‡	—‡
T35G	−0.31 ± 0.04	—‡	—‡	—‡
I42V	0.72 ± 0.08	0.20 ± 0.11	0.17 ± 0.09	0.61 ± 0.06
V44A	3.66 ± 0.16	0.04 ± 0.03	−0.04 ± 0.01	0.39 ± 0.03
A46G	0.88 ± 0.04	0.28 ± 0.17	0.18 ± 0.05	0.67 ± 0.05
I47V	0.11 ± 0.04	—‡	—‡	—‡
A52G	2.22 ± 0.16	0.00 ± 0.05	0.02 ± 0.03	0.20 ± 0.03
A53G	2.39 ± 0.16	−0.01 ± 0.04	0.04 ± 0.03	0.12 ± 0.03
I59V	1.08 ± 0.09	0.06 ± 0.06	0.08 ± 0.06	0.41 ± 0.06
V65A	4.01 ± 0.15	0.49 ± 0.02	0.41 ± 0.09	0.60 ± 0.09
L66A	2.34 ± 0.14	0.57 ± 0.03	0.45 ± 0.06	0.81 ± 0.07
V68A	2.17 ± 0.16	0.62 ± 0.05	0.45 ± 0.03	0.80 ± 0.09
L73A	3.07 ± 0.14	0.34 ± 0.02	0.25 ± 0.04	0.42 ± 0.05
K79A	−0.67 ± 0.05	—§	—§	—§
K79G	1.21 ± 0.10	0.41 ± 0.06§	0.45 ± 0.09§	0.96 ± 0.04§
A81G	1.86 ± 0.13	0.54 ± 0.04	0.45 ± 0.08	0.91 ± 0.04
E83A	0.82 ± 0.04	—§	—§	—§
E83G	1.28 ± 0.04	0.43 ± 0.06§	0.39 ± 0.02§	0.77 ± 0.05§
L85A	4.20 ± 0.16	0.33 ± 0.02	0.18 ± 0.07	0.49 ± 0.09
V92A	1.56 ± 0.11	0.72 ± 0.1	0.70 ± 0.06	0.72 ± 0.09
L94A	4.50 ± 0.13	0.48 ± 0.01	0.38 ± 0.05	0.57 ± 0.12
L96A	3.36 ± 0.14	0.57 ± 0.02	0.57 ± 0.09	0.76 ± 0.11

Calculated in the presence (∗) and

in the absence (†) of 0.4 M sodium sulfate using standard equations. In the case of PDZ2, Φ values were found to be essentially insensitive to denaturant concentrations.

^‡These mutants display thermodynamic stabilities similar to wild-type PDZ2 (ΔΔG < 0.5 kcal·mol⁻¹), which prevents accurate calculation of Φ values.

^§Ala—Gly scanning mutants. In order to detect structure formation in helix2, the two solvent exposed residues in such a helix (K79 and E83) were mutated into Ala and Gly. A Φ value can be then calculated by comparing the folding kinetics of the Gly variant with its Ala counterpart. Characterization of the shorter helix1 was obtained directly from A52G and A53G mutants.