Purification of peptides with differential cytolytic activities from the skin secretions of the Central American frog, Lithobates vaillanti (Ranidae)

J. Michael Conlon, Haider Raza, Laurent Coquet, Thierry Jouenne, Jérôme Leprince, Hubert Vaudry, Jay D. King

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Peptide-based defenses of ranid frogs from Mexico and Central America have been studied in much less detail than those from North America. Peptides belonging to the brevinin-1 (5 peptides), palustrin-2 (1 peptide), and ranatuerin-2 (3 peptides) families were isolated from norepinephrine-stimulated skin secretions of the Costa Rican frog, Lithobates vaillanti (Ranidae) and characterized structurally. Brevinin-1VLa (FLGAIAGVAAKFLPKVFCFITKKC) and brevinin-1VLc (FLPVIASVAAKVLPK VFCFITKKC) showed particularly high growth-inhibitory potency (MIC ≤ 3 μM) against a Gram-positive microorganism Staphylococcus aureus and the opportunistic yeast pathogen Candida albicans and potent cytolytic activity (LC50 ≤ 8 μM) against both human erythrocytes and HepG2 hepatoma-derived cells. The peptides were also active against a Gram-negative microorganism Escherichia coli (MIC ≤ 50 μM). Substitutions in brevinin-1VLd (Lys11 → Asn) and brevinin-1VLe (Lys11 → Ser) that decrease cationicity result in loss of activity against E. coli. Ranatuerin-2VLb (GIMDTIKGAAKDLAGQLLDKLKCKITKC) showed relatively weak antimicrobial activity (MIC ≥ 75 μM) but selective cytolytic activity against HepG2 tumor cells (LC50 = 30 μM) compared with erythrocytes (LC50 > 200 μM). In addition, a dodecapeptide (RICYAMWIPYPC) were isolated from the secretions that were devoid of antimicrobial activity. This component contains an Ala-Met bond that constitutes the scissile bond in the selective elastase inhibitor, elafin but the peptide did not inhibit pancreatic elastase at concentrations up to 100 μM.

Original languageEnglish
Pages (from-to)150-154
Number of pages5
JournalComparative Biochemistry and Physiology - C Toxicology and Pharmacology
Volume150
Issue number2
DOIs
Publication statusPublished (in print/issue) - Aug 2009

Keywords

  • Antimicrobial peptide
  • Brevinin-1
  • Lithobates
  • Palustrin-2
  • Ranatuerin-2

Fingerprint

Dive into the research topics of 'Purification of peptides with differential cytolytic activities from the skin secretions of the Central American frog, Lithobates vaillanti (Ranidae)'. Together they form a unique fingerprint.

Cite this