1. A family of kassinatuerin-2 related peptides from the skin secretion of the African hyperoliid frog, Kassina maculata
Lei Wang, Mei Zhou, Stephanie McGrath, Tianbao Chen, Sean P Gorman, Brian Walker, Chris Shaw Peptides. 2009 Aug;30(8):1428-33. doi: 10.1016/j.peptides.2009.04.021. Epub 2009 May 7.
We describe the isolation and structural characterization of a family of antimicrobial peptides related to kassinatuerin-2, from the skin secretion of the African hyperoliid frog, Kassina maculata. All four peptides, designated kassinatuerin-2Ma through Md, are C-terminally-amidated 20-mers with the consensus sequence - FX(1)GAIAAALPHVIX(2)AIKNAL - where X(1)=L/F/V/I and X2=S/N. All four peptides are encoded by precursors of 69 amino acids. Synthetic replicates of all kassinatuerin-2 related peptides displayed a potent inhibitory activity against Staphylococcus aureus with a minimal inhibitory concentration of 16microM, at which concentration, however, they effected 18% haemolysis of horse erythrocytes after 2h. Despite obvious membranolytic properties, all peptides were ineffective at inhibiting the growth of Escherichia coli at concentrations up to 200microM and were relatively ineffective against Candida albicans (MIC 120microM). The kassinatuerin-2 related peptides of K. maculata skin secretion thus possess a discrete antimicrobial and weak haemolytic activity in contrast to the prototype kassinatuerin-2 from the skin secretion of Kassina senegalensis.
2. Kassinakinin S: a novel histamine-releasing heptadecapeptide from frog (Kassina senegalensis) skin secretion
Tianbao Chen, Cherith N Reid, Brian Walker, Mei Zhou, Chris Shaw Biochem Biophys Res Commun. 2005 Nov 18;337(2):474-80. doi: 10.1016/j.bbrc.2005.09.072. Epub 2005 Sep 21.
Amphibian defensive skin secretions remain a largely untapped resource for the peptide biochemist with an interest in the identification, structural characterization, and precursor cDNA cloning of novel bioactive peptides. Here we report the isolation, structural characterization, functional profiling, and nucleotide sequence of precursor cDNA of a novel histamine-releasing heptadecapeptide, FIPVTLLALHKIKEKLN-amide, from the defensive skin secretion of the African running frog, Kassina senegalensis. This peptide was found to be a potent histamine secretagogue (EC(50) = 6 microM; maximal release = 25 microM) in a rat peritoneal mast cell model system and was accordingly named kassinakinin S. The open-reading frame of the cDNA encoding prepro-kassinakinin S was found to consist of 71 amino acid residues containing a single copy of kassinakinin S and its glycyl residue amide donor at the C-terminus. Kassinakinin S can thus be added to the growing list of amphibian skin bioactive peptide prototypes.
3. FMRFamide-related peptides (FaRPs): A new family of peptides from amphibian defensive skin secretions
Lei Wang, Anita Smyth, Anders H Johnsen, Mei Zhou, Tianbao Chen, Brian Walker, Chris Shaw Biochem Biophys Res Commun. 2009 Jun 5;383(3):314-9. doi: 10.1016/j.bbrc.2009.04.002. Epub 2009 Apr 7.
Amphibian defensive skin secretions are known to contain a plethora of biologically-active peptides that are often structural and functional analogues of vertebrate neuropeptides. Here we report the structures of two invertebrate neuropeptide analogues, IPPQFMRF amide (IF-8 amide) and EGDEDEFLRF amide (EF-10 amide), from the defensive skin secretions of two different species of African hyperoliid frogs, Kassina maculata and Phylictimantis verrucosus, respectively. These represent the first canonical FMRF amide-related peptides (FaRPs) from a vertebrate source. The cDNA encoding IF-8 amide was cloned from a skin secretion library and found to contain a single copy of the peptide located at the C-terminus of a 58 amino acid residue open-reading frame. These data extend the potential targets of the defensive arsenal of amphibian tegumental secretions to parasitic/predatory invertebrates and the novel peptides described may represent the first vertebrate peptidic endectocides.
