An antimicrobial peptide from the skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae)

Louise A. Rollins-Smith, Jay D. King, Per F. Nielsen, Agnes Sonnevend, J. Michael Conlon

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

A 25 amino-acid-residue, C-terminally α-amidated peptide with antimicrobial activity, which has been termed fallaxin, was isolated in high yield from the norepinephrine-stimulated skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae). The amino acid sequence of the peptide (Gly-Val-Val-Asp-Ile-Leu-Lys-Gly-Ala-Ala-Lys-Asp-Ile-Ala-Gly-His- Leu-Ala-Ser-Lys-Val-Met-Asn-Lys-Leu•NH 2) shows structural similarity with members of the ranatuerin-2 family previously isolated from the skins of frogs of the genus Rana that are only distantly related to the Leptodactylidae. This observation is consistent with the hypothesis that many frog skin antimicrobial peptides are related evolutionarily, having arisen from multiple duplications of an ancestral gene that existed before the radiation of the different families. Fallaxin inhibited the growth of reference strains of Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae) but with relatively low potency (MIC≥20 μM) and was inactive against the Gram-positive bacterium (Staphylococcus aureus) and the yeast Candida albicans. The hemolytic activity of fallaxin was very low (HC 50>200 μM). A second peptide, comprising residues (1-22) of fallaxin, was also isolated from the skin secretions but this component was inactive against the microorganisms tested.

Original languageEnglish
Pages (from-to)173-178
Number of pages6
JournalRegulatory Peptides
Volume124
Issue number1-3
DOIs
Publication statusPublished - Jan 15 2005

Keywords

  • Fallaxin
  • Gram-negative bacteria
  • HPLC
  • Ranatuerin-2

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Clinical Biochemistry
  • Cellular and Molecular Neuroscience

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