Structural and Mechanismic Studies of Lactophoricin Analog, Novel Antibacterial Peptide

Naturally derived antibacterial peptides exhibit excellent pharmacological action without the risk of resistance, suggesting a potential role as biologicals. Lactophoricin-I (LPcin-I), found in the proteose peptone component-3 (PP3; lactophorin) of bovine milk, is known to exhibit antibiotic activity against Gram-positive and Gram-negative bacteria. Accordingly, we derived a new antibacterial peptide and investigated its structure-function relationship. This study was initiated by designing antibacterial peptide analogs with better antibacterial activity, less cytotoxicity, and shorter amino acid sequences based on LPcin-I. The structural properties of antibacterial peptide analogs were investigated via spectroscopic analysis, and the antibacterial activity was confirmed by measurement of the minimal inhibitory concentration (MIC). The structure and mechanism of the antibacterial peptide analog in the cell membrane were also studied via solution-state nuclear magnetic resonance (NMR) and solid-state NMR spectroscopy. Through N-15 one-dimensional and two-dimensional NMR experiments and P-31 NMR experiments, we suggest the 3D morphology and antibacterial mechanism in the phospholipid bilayer of the LPcin analog. This study is expected to establish a system for the development of novel antibacterial peptides and to establish a theoretical basis for research into antibiotic substitutes.

Automated summary

This study focused on deriving a new antibacterial peptide with improved activity and less toxicity based on a naturally derived antibacterial peptide, investigating its structure-function relationship through spectroscopic analysis and measurement of minimal inhibitory concentration, as well as studying the structure and mechanism of the antibacterial peptide analog in the cell membrane through nuclear magnetic resonance (NMR) spectroscopy. The study aims to establish a system for the development of novel antibacterial peptides and provide a theoretical basis for research into antibiotic substitutes.