Aegerolysin protein family comprises over 350 homologs from different taxonomic groups. They are small (13-20 kDa), β-structured proteins with low isoelectric point and poorly known biological role. Aegerolysins interact with lipid membranes and when complexed with a protein partner, form transmembrane pores. Aegerolysins are commercially used as insecticides due to their binding to ceramide phosphoethanolamine in invertebrate membranes. Genes for aegerolysin and its hypothetical protein partner are also found in bacteria Spirosoma linguale. Recombinant plasmids containing both genes, for the aegerolysin SlinAg and for its putative protein partner SlinB were recently constructed, however only the aegerolysin protein was purified. The aim of this master thesis was to acquire both recombinant proteins in concentrations high enough to analyse their interaction with artificial lipid vesicles and to analyse their potential insecticidal activity. Both recombinant proteins from bacteria Escherichia coli were successfully synthesized and purified. Recombinant protein SlinAg was purified by nickel affinity chromatography from the soluable fraction and from inclusion bodies. We purified recombinant protein SlinB from inclusion bodies and optimized its renaturation. Experiments with artificial vesicles did not show binding specificity for the selected lipids. Preliminary insecticidal tests showed that bacteria Spirosoma linguale is not toxic to western corn rootworm larvae.
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