A new antifungal peptide from the seeds of Phytolacca americana: characterization, amino acid sequence and cDNA cloning

An antifungal peptide from seeds of Phytolacca americana, designated PAFP-s , has been isolated. The peptide is highly basic and consists of 38 residue s with three disulfide bridges. Its molecular mass of 3929.0 was determined by mass spectrometry. The complete amino acid sequence was obtained from a utomated Edman degradation, and cDNA cloning was successfully performed by 3'-RACE. The deduced amino acid sequence of a partial cDNA corresponded to the amino acid sequence from chemical sequencing. PAFP-s exhibited a broad spectrum of antifungal activity, and its activities differed among various fungi. PAFP-s displayed no inhibitory activity towards Escherichia coli. PA FP-s shows significant sequence similarities and the same cysteine motif wi th Mj-AMPs, antimicrobial peptides from seeds of Mirabilis jalapa belonging to the knottin-type antimicrobial peptide. (C) 1999 Elsevier Science B.V. All rights reserved.