Enhancing the antimicrobial activity of Sus scrofa lysozyme by N-terminal fusion of a sextuple unique homologous peptide

Abstract

Sus scrofa lysozyme (SSL), an important component of the pig immune system, is a potential candidate to replace antibiotics in feed. However, there is little antimicrobial activity of natural SSL against gram-negative bacteria, which limits its application. In this study, a unique peptide (A-W-V-A-W-K) with antimicrobial activity against gram-negative bacteria was discovered and purified from trypsin hydrolysate of natural SSL. This unique peptide was fused to natural SSL and the recombinant fused SSL exhibited improved activity against gram-negative bacteria. The N-terminal fusion likely increased the membrane penetrability and induced programmed bacterial cell death. The recombinant fused SSL also showed higher activity against some gram-positive bacteria with O-acetylation. By N-terminal fusion of the sextuple peptide, the anti-microbial activity, either to gram-positive or negative bacteria, of the recombinant SSL was higher than the fusion of only one copy of the peptide. This study provides a general, feasible, and highly useful strategy to enhance the antimicrobial activity of lysozyme.

Keywords: Acetonitrile (PubChem CID: 6342); Antibiotic; Antimicrobial activity; Carboxyfluorescein diacetate (PubChem CID: 44398788); Fluorescein isothiocyanate (PubChem CID: 18730); IPTG (PubChem CID: 656894); Kanamycin (PubChem CID: 6032); Penetrability; Peptide; Phosphatidylserine (PubChem CID: 6323481); Programmed cell death; Propidium iodide (PubChem CID: 104981); Sus scrofa lysozyme (SSL); Trifluoroacetic acid (PubChem CID: 6422).