Identification and structure–activity relationship of an antimicrobial peptide of the palustrin-2 family isolated from the skin of the endangered frog Odorrana ishikawae

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2011-10, Vol.32 (10), p.2052-2057
• Main Authors: Iwakoshi-Ukena, Eiko, Okada, Genya, Okimoto, Aiko, Fujii, Tamotsu, Sumida, Masayuki, Ukena, Kazuyoshi
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acids; Animals; Anti-Infective Agents - chemistry; Anti-Infective Agents - metabolism; anti-infective properties; antibiotic resistance; Antimicrobial Cationic Peptides - chemistry; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Antimicrobial peptide; antimicrobial peptides; Biological and medical sciences; Candida albicans; complementary DNA; Escherichia coli; Frog skin; frogs; Fundamental and applied biological sciences. Psychology; Innate immunity; methicillin; Microbial Sensitivity Tests; Microorganism; microorganisms; Molecular Sequence Data; Odorrana; Rana; Ranidae - anatomy & histology; Ranidae - immunology; Sequence Alignment; signal peptide; Skin - chemistry; Staphylococcus aureus; Structure-Activity Relationship; structure-activity relationships; synthetic peptides; Vertebrates: endocrinology
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/j.peptides.2011.08.024

► An antimicrobial peptide of the palustrin-2 family was isolated from the skin of the endangered frog Odorrana ishikawae. ► The peptide consists of 36 amino acid residues including 7 amino acids C-terminal to the cyclic heptapeptide Rana box domain. ► This peptide showed broad-spectrum growth inhibition against several microorganisms. ► Some synthetic analog peptides possessed greater antimicrobial activities than the native structure. Recently, we identified nine novel antimicrobial peptides from the skin of the endangered anuran species, Odorrana ishikawae, to assess its innate immune system. In this study an additional antimicrobial peptide was initially isolated based on antimicrobial activity against Escherichia coli. The new antimicrobial peptide belonging to the palustrin-2 family was named palustrin-2ISb. It consists of 36 amino acid residues including 7 amino acids C-terminal to the cyclic heptapeptide Rana box domain. The peptide's primary structure suggests a close relationship with the Chinese odorous frog, Odorrana grahami. The cloned cDNA encoding the precursor protein contained a signal peptide, an N-terminal acidic spacer domain, a Lys-Arg processing site and the C-terminal precursor antimicrobial peptide. It also contained 3 amino acid residues at the C-terminus not found in the mature peptide. Finally, the antimicrobial activities against four microorganisms (E. coli, Staphylococcus aureus, methicillin-resistant S. aureus and Candida albicans) were investigated using several synthetic peptides. A 29 amino acid truncated form of the peptide, lacking the 7 amino acids C-terminal to the Rana box, possessed greater antimicrobial activities than the native structure.