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

► 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.