Table 1.
Folding free energies of PEGylated and PEG-stapled WW, SH3, and GCN4 variants. a
| Protein | Tm (°C) | ΔG (kcal/mol) | Impact of Stapling | ||
|---|---|---|---|---|---|
| ΔΔG (kcal/mol) | ΔΔH (kcal/mol) | -TΔΔS (kcal/mol) | |||
| 16/32–00 | 49.2 ± 0.6 | 0.00 ± 0.04 | |||
| 16/32-o44 | 54.0 ± 0.2 | −0.40 ± 0.02 | |||
| s16/32-o44 | 71.7 ± 0.3 | −1.51 ± 0.04 | −1.11 ± 0.04 | 2.1 ± 0.9 | −3.2 ± 0.9 |
| 16/32-c44 | 54.2 ± 0.2 | −0.44 ± 0.02 | |||
| s16/32-c44 | 71.4 ± 0.1 | −1.68 ± 0.03 | −1.24 ± 0.03 | 8.3 ± 0.8 | −9.6 ± 0.8 |
| 14/30–00 | 28.6 ± 0.2 | 0.00 ± 0.01 | |||
| 14/30-o55 | 33.2 ± 0.1 | −0.34 ± 0.01 | |||
| s14/30-o55 | 39.5 ± 0.6 | −0.83 ± 0.05 | −0.49 ± 0.05 | −1.2 ± 0.9 | 0.7 ± 0.9 |
| 14/30-c44 | 30.5 ± 0.2 | −0.13 ± 0.01 | |||
| s14/30-c44 | 41.3 ± 0.1 | −0.73 ± 0.01 | −0.61 ± 0.02 | 1.9 ± 0.4 | −2.5 ± 0.4 |
| 20/37–00 | 61.1 ± 0.3 | 0.00 ± 0.02 | |||
| s20/37-o44 | 76.0 ± 0.8 | −0.94 ± 0.06 | −0.93 ± 0.07 | 9.9 ± 1.3 | −10.8 ± 1.3 |
| d27/29’-c40 | 41.1 ± 0.2 | 0.00 ± 0.02 | |||
| sd27/29’-c40 | 48.2 ± 0.1 | −0.65 ± 0.01 | −0.65 ± 0.02 | 1.3 ± 0.6 | −1.9 ± 0.6 |
| 27/29’-c40 | 34.8 | --- | |||
| s27/29’-c40 | 82.0 ± 0.2 | --- | --- | --- | --- |
Folding free energies for each variant are given ± std. error in kcal/mol at the melting temperature of its non-stapled non-PEGylated counterpart. WW variants 16/32–00, 14/30–00 and SH3 variant 20/37–00 and their derivatives were analyzed at 50 μM protein concentration in 20 mM sodium phosphate buffer (pH 7). GCN4 disulfide-bound heterodimer d27/29’-c40 and its triazole-stapled counterpart sd27/29’-c40 were analyzed at 15 μM protein concentration in 20 mM sodium phosphate buffer (pH 7) + 4.0 M GdnHCl. GCN4 noncovalent heterodimer 27/29’-c40 and its triazole-stapled counterpart s27/29’-c40 were analyzed at 15 μM protein concentration in 20 mM sodium phosphate buffer (pH 7) + 0.5 M GdnHCl.