Table 1.
Folding thermodynamics of wild-type GB1 and backbone-modified analogues.
| Protein | 2° Structure Modified | Tm (°C)a | ΔTm (°C)b | ΔΔGfold (kcal mol-1)c |
|---|---|---|---|---|
| 1 | none | 81.4 ± 0.1 | − | − |
| 2 | Helix | 61.6 ± 0.1 | −19.8 | +3.2 ± 0.1 |
| 3 | Loops | 77.6 ± 0.1 | −3.8 | +0.6 ± 0.1 |
| 4 | Sheet | 75.6 ± 0.1 | −5.8 | +0.9 ± 0.1 |
| 5 | Turns | 67.6 ± 0.1 | −13.8 | +2.2 ± 0.1 |
| 6 | All | ∼31d | −50 | +8 |
| 8 | All | ∼82e | ∼0 | ∼0 |
a
Midpoint of the thermal transition observed by CD at 220 nm for a 40 μM protein sample in 20 mM phosphate pH 7; estimated errors are uncertainty from the fit.
b
Change in Tm vs. wild-type (1).
c
Change in folding free energy vs. 1.
d
A complete folded baseline was not observed.
e
A complete unfolded baseline was not observed.