Table 1.
β-Hairpin population calculated at each indicator residue (listed from N to C terminus) from δαH data, according to Eq. 1
| Peptide | Val #1 Pop. | Val #2 Pop. | Orn Pop. | Ile Pop. | Average ΔΔG (kcal/mol) |
|---|---|---|---|---|---|
| DP | 70% | 76% | 65% | 59% | — |
| DP-TT | 80% | 84% | 76% | 72% | −0.29 ± 0.03 |
| DP-TT2 | 85% | 92% | 79% | 80% | −0.53 ± 0.21 |
| DP-ST | 78% | 88% | 74% | 70% | −0.29 ± 0.17 |
| DP-ST2 | 78% | 80% | 71% | 69% | −0.17 ± 0.10 |
| DP-TA | 89% | 104% | 85% | 78% | −0.59 ± 0.14 |
| DP-TA2 | 83% | 92% | 82% | 74% | −0.50 ± 0.24 |
| DP-ST/Y | 81% | 92% | 82% | 74% | −0.48 ± 0.25 |
| DP-ST/Y2 | 78% | 84% | 71% | 70% | −0.22 ± 0.10 |
The % β-hairpin values have an uncertainty of ±2–4%, which arises from the ±0.01 ppm uncertainty in δαH. ΔΔG for each 16- or 20-mer, relative to 12-mer DP, was calculated for each residue in the usual way [(Keq for β-hairpin formation = (δobs − δU)/(δF − δobs); ΔG = −RTInKeq; ΔΔG = ΔG (16- or 20-mer) − ΔG (12-mer)]. The uncertainty in ΔΔG was calculated by using the standard deviation in ΔΔG for the four indicator residues in each peptide and Student's t-test at the 95% confidence level (this procedure treats each residue as an independent reporter of peptide ΔΔG).