Figure 7. Glycerol prevents the thermal unfolding of RTA in either the absence or presence of POPC/POPG.

(A–B): The temperature-induced unfolding of RTA secondary structure in the presence of 10% glycerol (A) or in the presence of both 10% glycerol and POPC/POPG (B) was monitored by far-UV CD. In panel (B), 100 nm LUVs containing 80% POPC and 20% POPG were introduced 30 min after toxin exposure to 10% glycerol at 20°C. Data were recorded with 2 µM RTA in pH 7.2 buffer. The change in color from blue to red corresponds to a change in temperature from 20°C to 60°C. (C): The mean residue molar ellipticities at 208 nm ([θ]₂₀₈) in the presence of either 10% glycerol (green) or both 10% glycerol and POPC/POPG (blue) were plotted as a function of temperature.