Figure 9.
Effect of dioxane on the EPR spectrum from BtuB 156R1. Spectra are shown in the absence of dioxane (black trace) and in the presence of 5% v/v (blue trace) and 10% (red trace) dioxane. In POPC bilayers, dioxane increases the population of the fast component, consistent with the proposal that the slow label conformer results from an interaction of the label with a hydrophobic pocket on the protein surface. In DiErPC bilayers, dioxane does not affect the rotameric equilibrium, presumably because this interaction is much stronger in lipid bilayers of greater thickness.
