Figure 4: Structural characterization of Y406A pores.

From: Engineering a pH responsive pore forming protein

Figure 4

(a) Permeabilization of GUVs (left, red membrane stain) for fluorescent dextran (middle, green stain) by the LLO and Y406A (the right panels represent the superimposed images). The concentration of proteins was 100 nM in buffer with pH 5.5 and at room temperature. (b) Quantitative comparison of permeabilizing activity of LLO and Y406A for fluorescent dextran 70 kDa after 30 min incubation. Control did not contain any protein. An average ± S.D. is shown in grey, together with values for each individual GUV. Each point represents permeabilisation for a single vesicle; ~100 GUVs were analysed for each protein. (c) TEM images of multilamellar vesicles composed of POPC:Chol incubated in the presence of the LLO or Y406A at pH 5.5 and at room temperature. Two selected assemblies are enlarged in the inset. (d) AFM image of LLO (top) and Y406A (bottom) arcs as seen on POPC:Chol 1:1 lipid membrane at pH 5.6 and room temperature and associated quantification of Y406A arcs.