Design and characterization of a bifunctional bybrid antibacterial peptide LLH for bactericidal/endotoxin neutralization effects

Objective:To design a bi-functional antimicrobial peptide with bactericidal and endotoxin neutralization activity,and explore its bactericidal properties.Methods:The LBP(86-99)peptides and HLF(1-11)peptides were connected by a GGGS flexible 4-peptide linker to obtain the bi-functional antimicrobial peptide,which was named LLH.The secondary structure characteristics of LLH were analyzed by Emboss software.The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of LLH against Escherichia coli ATCC25922 and DH5αwere determined by the microtiter broth dilution method.The bactericidal kinetics of LLH was characterized and its effect on endotoxin neutralization was determined.The hemolysis of LLH was evaluated.Results:LLH carried a positive charge of+9,exhibitedβ-folding andβ-corner structure,and had strong hydrophobicity.The MIC of LLH against Escherichia coli ATCC25922 and DH5αwas 4μM,and the MBC of LLH against Escherichia coli ATCC25922 and DH5αwas 8 and 4μM,respectively.LLH showed rapid bactericidal effects and significantly neutralized the endotoxin released in the sterilization process as well as reducing release of endotoxin.LLH showed no significant hemolysis at concentrations up to 400μg/mL.Conclusion:LLH produces dual effects of rapid sterilization and endotoxin neutralization,and does not induce significant hemolysis.