Figure 4. PolyQ insertions destabilize BlaP and the extent of destabilization is largely independent of the polyQ length.

(A) Normalized urea-induced unfolding transitions at pH 7.5 and 25°C and (B) normalized heat-induced unfolding transitions at pH 7.5, monitored by the changes in fluorescence intensity at 323 nm (filled circles) and in ellipticty at 222 nm (open circles), using a protein concentration of 4.6 µM. BlaP (blue), BlaP(Gln)₂₃ (red), BlaP(Gln)₃₀ (green), BlaP(Gln)₅₅ (pink) and BlaP(Gln)₇₉ (cyan). Non-normalized data were analysed on the basis of a two-state model and the values of the thermodynamic parameters obtained are reported in Table 3.