Important feature of aegerolysins is binding to various lipids, lipid vesicles or lipid bilayers. Aegerolysins can form pores directly or in combination with a partnering protein containing a MACPF (membrane attack complex/perforin) domain. They can therefore be used as specific lipid markers and for the pest control. One of the important binding partners of aegerolysins is ceramide phosphoethanolamine (CPE), a sphingolipid that is very abundant in the membranes of the invertebrates (particularly insects) and protozoa. Within M. Sc. Thesis we focused on three aegerolysins: nigerolysin A2 (NigA2) from the filamentous fungus Aspergillus niger, pleurotolysin A2 (PlyA2) from the mushroom Pleurotus eryngii and RahU from the bacterium Pseudomonas aeruginosa. Our aim was to determine their binding characteristics to the lipid vesicles composed of different molar ratios of CPE and cholesterol (Chol) or other sterols using sedimentation assay and surface plasmon resonance. Monitoring the calcein release from various lipid vesicles, the permeabilization activity of aegerolysin PlyA2 in combination with its partnering protein, pleurotolysin B (PlyB), was tested. We have discovered that PlyA2 is the most appropriate marker for labeling membranes containg CPE, while NigA2 and RahU are less suitable. For the successful binding of PlyA2 to lipid vesicles, at least 5 mol % of CPE and 30 mol % of Chol are required. In addition, PlyA2 binds to lipid vesicles composed of CPE and various sterols (the strongest binding was detected in the case of 7-dehydrocholesterol and β-sitosterol). We have also shown that PlyA2 in combination with PlyB permeabilizes membranes of lipid vesicles containing CPE and various sterols, indicating their potential to be used as pest control agents.
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