Objective: To construct a targeting bactericidal peptide machine by fusing two minidomains with different bioactivities and different protein origins.
Methods: Such fusion peptide was constructed by linking the gene of Staphylococcal AgrD pheromone with the gene of C-terminal (I626) of colicin Ia pore-forming region (K544-I626) with site-directed mutation. Mutated plasmid was transformed into E. coli TG1 cells to produce fusion peptide, peptides were purified by CM sepharose ion-exchange column. In vitro bactericidal assays were made to identify the bioactivity of fusion peptide.
Results: Fusion peptide presented a specific bactericidal activity which was over one hundred times as effective as that of penicillin/oxacillin against tested Staphylococcus aureus strains.
Conclusion: Fusion peptide behaved with a targeting bactericidal activity against Staphylococcus aureus which was lacking at two precursors, Staphylococcal pheromone and colicin Ia pore-forming region. These results suggest that an engineered multidomain protein machine with specific bactericidal activity has been constructed in the present study.