Purification and Characterization of Novel Anti-MRSA Peptides Produced by Brevibacillus sp. SPR-20

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 23; p. 8452
• Main Authors: Songnaka, Nuttapon, Lertcanawanichakul, Monthon, Hutapea, Albert M, Krobthong, Sucheewin, Yingchutrakul, Yodying, Atipairin, Apichart
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.12.2022; MDPI
• Subjects: Amino acids; Anti-Bacterial Agents - chemistry; anti-MRSA substances; Antibiotics; Antiinfectives and antibacterials; Antimicrobial activity; Antimicrobial agents; Antimicrobial peptides; Brevibacillus; Brevibacillus sp. SPR-20; Chromatography, Liquid; Circular dichroism; Dichroism; Drug resistance; Electron micrographs; Enzymes; Erythrocytes; Humans; Infections; Lysis; Membrane permeability; Membranes; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Molecular weight; Pathogens; peptide sequencing; Peptides; Peptides - chemistry; Protein purification; Proteolysis; Proteolytic enzymes; Public health; purification; Scanning electron microscopy; Soil bacteria; Soil microorganisms; Soil permeability; Staphylococcus aureus; Staphylococcus infections; Tandem Mass Spectrometry; Brevibacillus sp. SPR-20; peptide sequencing; anti-MRSA substances; purification; antimicrobial peptides
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27238452

Methicillin-resistant (MRSA) is listed as a high-priority pathogen because its infection is associated with a high mortality rate. It is urgent to search for new agents to treat such an infection. Our previous study isolated a soil bacterium ( sp. SPR-20), showing the highest antimicrobial activity against TISTR 517 and MRSA strains. The present study aimed to purify and characterize anti-MRSA substances produced by SPR-20. The result showed that five active substances (P1-P5) were found, and they were identified by LC-MS/MS that provided the peptide sequences of 14-15 residues. Circular dichroism showed that all peptides contained β-strand and disordered conformations as the major secondary structures. Only P1-P4 adopted more α-helix conformations when incubated with 50 mM SDS. These anti-MRSA peptides could inhibit and MRSA in concentrations of 2-32 μg/mL. P1 (NH -VVVNVLVKVLPPPVV-COOH) had the highest activity and was identified as a novel antimicrobial peptide (AMP). The stability study revealed that P1 was stable in response to temperature, proteolytic enzymes, surfactant, and pH. The electron micrograph showed that P1 induced bacterial membrane damage when treated at 1× MIC in the first hour of incubation. The killing kinetics of P1 was dependent on concentration and time. Mechanisms of P1 on tested pathogens involved membrane permeability, leakage of genetic material, and cell lysis. The P1 peptide at a concentration up to 32 μg/mL showed hemolysis of less than 10%, supporting its safety for human erythrocytes. This study provides promising anti-MRSA peptides that might be developed for effective antibiotics in the post-antibiotic era.