Heterologous expression of a broad-spectrum chimeric antimicrobial peptide in Lactococcus lactis: Its safety and molecular modeling evaluation

Abstract

Over the last decade, global increase in antibiotic consumption is a major concern in the word. Antimicrobial<br><br>peptides (AMPs) known as potential alternative and were considered as a safe antimicrobial agent. However,<br><br>current approaches for production and purification of AMPs are costly and time-consuming. Here we show that<br><br>heterologous expression of a chimeric peptide was successfully developed in Lactococcus lactis as a safe and costeffective<br><br>recombinant protein expression platform. Minimum inhibitory concentrations (MICs) of His-tag purified<br><br>peptide was determined against a broad spectrum of human pathogenic bacteria consistence of Grampositive,<br><br>Gram-negative and resistance strains in deferent range from 7.24 ± 0.4 to 156.24 ± 3.0 μg/mL.<br><br>Furthermore, our results showed that the peptide was not toxic to HEK and HeLa cells and even at concentrations<br><br>as high as 250 μg/mL exhibited minimal hemolysis against RBCs. Additional characteristics such as thermal,<br><br>protease and 50% human plasma stability were determined for cLFchimera. Molecular modeling analysis demonstrated<br><br>that fusion of His-tag to the C-terminal of chimeric peptide increased peptide stability during 10 ns<br><br>simulation in water. Overall, the chimeric peptide has a considerable antibacterial activity with low hemolysis,<br><br>low or none in toxicity and good temperature resistance and also high stability in serum. We anticipate the<br><br>established expression system could be developed and used more effectively in probiotic strains in future studies.