Illustration of the determination of the radius of pores formed by nine of the different combinations of class S and class F proteins. Permeabilizations were assessed by variations of the mean value of the FSC in the presence of PEG molecules of different hydrodynamic radii. LukF-PV, LukF-PV N123-G127, and LukF-PV G130D were combined with LukS-PV, HlgA, and HlgC. As the FSC values did not increase from 10 to 20 or 30 min after toxin application under the experimental conditions, only the values obtained at 10 min are shown.