Ostreolysin A (OlyA) from oyster mushroom (Pleurotus ostreatus) is a member of the aegerolysin protein family. OlyA recognizes and binds to membrane domains enriched in cholesterol and sphingomyelin, so-called lipid rafts, and to ceramide phosphoethanolamine (CPE), a sphingolipid specific for invertebrates and some Gram negative bacteria. Due to previously mentioned features, OlyA and other aegerolysins have great biotechnological potential which is particulary shown in fields of clinical diagnostics and agriculture. Some of the aegerolysins, combined with their partner proteins, can act as pore formers and cam exert hemolytic and cytolytic effects. The key to successful use of aegerolysins and development of potential applications is in identifying their targets and in understanding their binding specificity. Using the dot blot method, we tested the interaction between fluorescently-labelled aegerolysin (OlyA-mCherry) and biofilm components of different strains of bacteria. We discovered bacterial biofilms do not contain targets that OlyA would recognize and bind. Using the dot blot and the far-eastern blot method, we examined the interaction of OlyA-mCherry with polar and non-polar lipids in bacteria, yeasts, filamentous fungus and in one species of archaea. The only apparent interaction was observed with non-polar lipids of a bacterium Prevotella spp. A signal was also shown in the case of OlyA interaction with polar and non-polar lipid fraction in P. aeruginosa EXB L-1125; however, these results are not reliable. According to the results we can, with great probability, confirm the specificity of OlyA interaction with CPE and the absence of additonal membrane targets in the majority of the tested microorganisms. We demonstrated that OlyA does not interact with bacterial biofilm components, nor with polar and non-polar lipids in bacteria, yeasts, filamentous fungus and archaea. The results thus allow further development of the use of aegerolysins in different biotechnological applications.
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