Figure 5
From: Conservation of folding and association within a family of spidroin N-terminal domains
Influence of salt on NTD monomer folding and stability. (a) Dependence of thermal stability on I measured in pH 7.0 buffered solutions using far-UV CD spectroscopy at 222 nm. Thermal denaturation mid-points are plotted versus I (Lh: blue squares, Lg: orange circles, Nc: green triangles, Ea: red diamonds). Solid lines are a guide to the eye. (b) Changes of free energy plotted versus the square root of I. Solid lines are linear data fits. Same colour code as in (a) applies. (c) Chemical denaturation of the Ea NTD measured in pH 7.0 buffered solution using far-UV CD (closed symbols) and Trp fluorescence spectroscopy (open symbols). Data were normalized to the folded fraction. Solid lines are data fits using a thermodynamic model for a two-state equilibrium. Magenta squares: 100 mM I; red circles: 200 mM I; cyan triangles: 350 mM I; blue diamonds: 500 mM I. (d) Plot of the change of free energy versus the square root of I measured using chemical denaturation. The solid line is a linear fit to the data.
