Sodium chloride augments the antibacterial activity of a novel penaeid shrimp-derived peptide (GPCR10) against halotolerant Staphylococcus aureus.

The activity of antimicrobial peptides (AMPs) can be enhanced by sodium chloride (NaCl), but whether this applies to halotolerant bacteria, such as Staphylococcus aureus , is unknown. Ten peptides with antimicrobial potential were identified from Penaeus vannamei using ultra-performance liquid chromatography-mass spectrometry and in silico analysis. One of the peptides, designated GPCR10 (LGLLLPALTLGTTHASGASGRR), was further explored against S. aureus in combination with NaCl treatment. Peptide GPCR10 had a minimum inhibitory concentration (MIC) of 62.5 μg/mL against S. aureus but when combined with NaCl (3.5% (w/v)), the MIC decreased to 3.9 μg/mL. Besides, the destruction of bacteria ultrastructure by GPCR10 was enhanced by NaCl, and its random coil structure was transformed to the α-helical form, thereby increasing its binding with bacteria membranes and permeability. These changes in GPCR10 resulted in bacteria destruction, extrusion of cellular content, and binding to bacteria DNA. Thus, low NaCl concentration could enhance the antibacterial activity of AMPs in food preservation. • Peptide GPCR10 is a novel antimicrobial peptide isolated from P. vannamei. • NaCl enhances the antibacterial activity of GPCR10 against S. aureus. • The permeability of GPCR10 across S. aureus increases with NaCl treatment. • Peptide GPCR10 binds bacterial genomic DNA to exert its antibacterial activity. [ABSTRACT FROM AUTHOR]