Table 3  Folding data for FADD DD helix scanning mutants
FADD DD variant  ΔGD-N (kcal mol-1)  ΔΔGD-N (kcal mol-1)  mD-N (kcal mol-1 M-1)  kf2 M (s-1)  Φ2 M
Helix 1
Cys98Ala  7.2   1.8  48
Cys98Gly  6.2  1.0  1.6  26  0.38
Asn102Ala  6.9   1.3  58
Asn102Gly  6.3  0.7  1.3  33  0.50
Helix2
Arg113Ala  6.5   1.2  52
Arg113Gly  5.4  1.1  1.1  38  0.17
Arg114Ala  6.4   1.6  46
Arg114Gly  5.0  1.4  1.6  28  0.20
Arg117Ala  6.3   1.2  47
Arg117Gly  5.2  1.1  1.1  31  0.23
Helix3
Asp127Ala  7.2   1.5  49
Asp127Gly  6.2  1.0  1.4  45  0.07
Ser128Ala  7.0   1.1  37
Ser128Gly  6.6  0.43  1.4  47  n.d.
Asp131Ala  7.5   1.4  44
Asp131Gly  6.5  1.0  1.4  46  –0.03
Arg132Ala  6.6   1.2  40
Arg132Gly  5.5  1.1  1.1  43  –0.04
Helix4
Thr138Ala  7.1   1.4  68
Thr138Gly  6.4  0.7  1.5  35  0.56
Glu139Ala  6.4   1.4  29
Glu139Gly  5.7  0.7  1.3  16  0.49
Arg142Ala  5.9   1.3  32
Arg142Gly  4.8  1.1  1.3  12  0.51
Glu143Ala  6.6   1.4  34
Glu143Gly  4.2  2.4  1.7  10  0.29
Arg146Ala  6.3    30
Arg146Gly  5.1  1.2  20  20  0.19
Asn150Ala  6.8   2.0  46
Asn150Gly  6.2  0.6  1.5  32  0.35
Helix5
Arg166Ala  4.6   1.3  22
Arg166Gly  3.7  0.9  1.6  13  0.30
Ser167Ala  7.6   1.7  69
Ser167Gly  6.4  1.3  1.7  28  0.42
Helix6
Asp175Ala  6.4   1.4  38
Asp175Gly  5.4  1.0  1.5  23  0.12
Gln178Ala  6.6   1.2  49
Gln178Gly  5.6  1.0  1.4  27  0.31
The ΔΔGD-N and Φ-values are determined for the Ala to Gly mutation. For clarity, errors are not shown in the table. The error in free energy measurements is in the range ± 0.1–0.2 kcal mol-1; the error in kf2M is ± 10% and the error in Φ is < 0.1. Note that Φ-values cannot be considered reliable if ΔΔGD-N is low,27 so Φ-values were not determined when ΔΔGD-N < 0.6 kcal mol- 1 (n.d.).