Figure 1.

Lysenin toxin membrane insertion is pH dependent. (a) HS-AFM movie frames of lysenin on an SM/Chol (1:1) bilayer (Movie S1). During HS-AFM movie acquisition, the pH is changed from 7.5 to <6.0, leading to an increased number of prepore lysenins (bright circles, protruding 5 nm) that insert into the membrane to become pore lysenins (dark circles, protruding ∼2.5 nm). (b) Graph of the number of prepores (i.e., image area occupied by pixels higher than the 3.75 nm threshold) as a function of movie acquisition time (black circles). The precise number of prepores and pores has been analyzed by cross-correlation searches at six specific time points (dashed lines) corresponding to the frames shown in (a). The average value of the SD maps shown in (c) reports about the topographical changes, i.e., the lateral mobility between subsequent frames, throughout movie acquisition. (c) SD maps over five consecutive frames (t − 4 s to t, where t is the time of recording the topography frames shown in a). To see this figure in color, go online.