Aegerolysins are a family of proteins that recognize and bind to specific membrane lipids or lipid mixtures, making them suitable as membrane lipid markers. Although they are present across all domains of life, those produced by fungi of the genus Pleurotus are the most well-studied. Most of these fungi harbour also the genes encoding proteins that contain the membrane attack complex/perforin (MACPF) domain. The combination of aegerolysin and its MACPF protein partner is lytic to cells that possess the aegerolysin lipid receptor, which makes them potential biopesticides. In the doctoral thesis, we recombinantly expressed eight novel aegerolysin proteins and five MACPF-domain proteins from the basidiomycetes Pleurotus pulmonarius, Heterobasidion irregulare, Trametes versicolor, Mucidula mucida, and Lepista nuda, and compared the activities of these proteins with the most studied aegerolysin, ostreolysin A6 and its MACPF protein partner pleurotolysin B from P. ostreatus. Most of these new proteins form active aegerolysin/MACPF cytolytic complexes upon binding of aegerolysin to specific sphingolipid-containing membranes. Some aegerolysins can also bind to selected glycerophospholipids, particularly phosphatidic acid and cardiolipin, but these interactions do not lead to pore formation. Our results indicate that some of these selected aegerolysins show potential as new molecular biosensors of membrane lipids or as biopesticides.
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