Antimicrobial function of SHβAP, a novel hemoglobin β chain-related antimicrobial peptide, isolated from the liver of skipjack tuna, Katsuwonus pelamis

• Published in: Fish & shellfish immunology 2014-03, Vol.37 (1), p.173-183
• Main Authors: Seo, Jung-Kil, Lee, Min Jeong, Jung, Hyun-Gyo, Go, Hye-Jin, Kim, Young Ja, Park, Nam Gyu
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - isolation & purification; Antimicrobial Cationic Peptides - metabolism; Antimicrobial Cationic Peptides - pharmacology; Antimicrobial peptide; Bacillus subtilis; Bacteria - drug effects; Base Sequence; beta-Globins - metabolism; Candida albicans; Chromatography, High Pressure Liquid; Computational Biology; Electrophoresis, Polyacrylamide Gel; Escherichia coli; Hemoglobin; Hemolysis - drug effects; Innate immunity; Katsuwonus; Liposomes - metabolism; Liver - metabolism; Models, Molecular; Molecular Sequence Data; Pelamis; Pseudomonas aeruginosa; Salmonella enterica; Sequence Analysis, DNA; Shigella sonnei; Skipjack tuna liver; Staphylococcus aureus; Streptococcus iniae; Thunnus; Tuna - genetics; Tuna - immunology; Tuna - metabolism; Vibrio parahaemolyticus
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2014.01.021

A 2.3 kDa of antimicrobial peptide was purified from an acidified liver extract of skipjack tuna, Katsuwonus pelamis, by preparative acid-urea–polyacrylamide gel electrophoresis and C18 reversed-phase HPLC. A comparison of the amino acid sequence of the purified peptide with those of other known polypeptides revealed high homology with the C-terminus of hemoglobin β-chain; thus, this peptide was designated as the Skipjack Hemoglobin β chain-related Antimicrobial Peptide (SHβAP). SHβAP showed potent antimicrobial activity against Gram-positive bacteria, such as Bacillus subtilis, Staphylococcus aureus, and Streptococcus iniae (minimal effective concentrations [MECs], 6.5–57.0 μg/mL), Gram-negative bacteria, such as Escherichia coli D31, Pseudomonas aeruginosa, Salmonella enterica, Shigella sonnei, and two Vibrio parahaemolyticus species (MECs, 2.0–19.0 μg/mL), and against Candida albicans (MEC; 12.0 μg/mL) without significant hemolytic activity. Antimicrobial activity of this peptide was heatstable and pH resistant but is sensitive to proteases and salt. SHβAP did not show membrane permeabilization and killing ability. The secondary structural prediction and the homology modeling expected that this peptide formed an amphipathic α-helical structure. This is the first report the purification of a novel antimicrobial peptide related to the C-terminus of hemoglobin β-chain from marine fish. •Hemoglobin β-chain related antimicrobial peptide (SHβAP) was purified from the liver of skipjack tuna.•SHβAP showed broad spectrum antimicrobial activity without hemolytic activity.•The action mode of SHβAP is bacteriostatic process rather than bactericidal one.•SHβAP is the first hemoglobin β-chain related antimicrobial peptide from marine fish.