Myticusin-beta, antimicrobial peptide from the marine bivalve, Mytilus coruscus

• Published in: Fish & shellfish immunology Vol. 99; pp. 342 - 352
• Main Authors: Oh, Ryunkyoung, Lee, Min Jeong, Kim, Young-Ok, Nam, Bo-Hye, Kong, Hee Jeong, Kim, Ju-Won, Park, Jung-yeon, Seo, Jung-Kil, Kim, Dong-Gyun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2020
• Subjects: Antimicrobial peptide; Myticusin-beta; Mytilus coruscus; Purification; Myticusin-beta; Mytilus coruscus; Purification; Antimicrobial peptide
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2020.02.020

We isolated and purified an antimicrobial peptide (AMP) from the mantle of the hard-shelled mussel, Mytilus coruscus. The peptide was purified through C18 reversed-phase high-performance liquid chromatography, and displayed antibacterial activity. Total molecular mass of 11,182 Da was determined using matrix-assisted laser desorption ionization time-of-flight mass spectrophotometry. The N-terminal 23-amino acid sequence of its purified peak was obtained through Edman degradation, revealing 82% identity with myticusin-1 of M. coruscus. Complete sequence of the target peptide was determined through cDNA cloning and rapid amplification of cDNA ends. The complete sequence comprised 574 bp with a 387-bp open reading frame (ORF) encoding 24 amino acids of a signal peptide and 104 amino acids of a mature peptide, which was named myticusin-beta. Furthermore, we discovered two novel isoforms of myticusin-beta. We constructed and expressed recombinant myticusin-beta, which displayed antimicrobial activity against gram-positive (Bacillus cereus, Bacillus subtilis, Clostridium perfringens, Staphylococcus aureus, Streptococcus iniae, Streptococcus mutans) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Vibrio alginolyticus, Klebsiella pneumoniae). Purified recombinant myticusin-beta also showed anti-parasitic activity at various concentrations. A short AMP analog was designed and synthesized based on the sequence of myticusin-beta, with markedly improved antimicrobial activity. Expression of myticusin-beta was detected in the mantle at the highest level, followed by hemocytes. The results obtained in this work suggest that myticusin-beta is an immune-related AMP of M. coruscus and an effective alternative to antibiotics. •We purified 11,182 Da of a novel antimicrobial peptide from mantle tissue extract of Mytilus coruscus.•TrxA-fused recombinant myticusin-beta exhibited antibacterial and anti-scuticociliate activity without causing hemolysis.•Designed and synthesized myticusin-beta analog revealed markedly improved antimicrobial activity.•Myticusin-beta is an immune-related antimicrobial peptide of Mytilus coruscus and an effective alternative to antibiotics.