Figure 8. The β4–β5 interaction in cholesterol bound ILY.

Cysteines were substituted for Val-322 in β4 of PFO or the analogous Val-349 in β4 of ILY and modified with NBD. Upon membrane binding β5 rotates away from β4, thus, the probe makes a transition from a nonpolar environment in the soluble monomer (solid line) to a polar environment in the membrane oligomer (dashed line), which results in the quenching of the NBD fluorescence [25]. The data are representative of 3 experiments.