Characterization of novel antimicrobial peptides from the skins of frogs of the Rana esculenta complex.
(2003)
Journal - Peptides (United States )
Abstract :
Rana esculenta is a hybridogenetic hybrid between Rana ridibunda and Rana lessonae and so is best considered as a complex of interbreeding species rather than a discrete single species. In this study, antimicrobial peptides were isolated from a pooled extract of the skins of specimens of the R. esculenta complex collected in the wild. In addition to several peptides belonging to the brevinin and esculentin families that have been previously isolated from skin secretions of a single specimen of R. esculenta, three newly described members of the brevinin-2 family (brevinin-2Ei, brevinin-2Ej, and brevinin-2Ek) and one member of the temporin family (temporin-1Ec) were purified and characterized. In addition, three structurally related peptides with no sequence similarity with antimicrobial peptides isolated from other species of ranid frogs, that potently and selectively inhibit the growth of the Gram-positive bacterium Escherichia coli (minimal inhibitory concentration (MIC<5 microM)), were identified. These peptides show limited amino acid sequence similarity to the homologous exon gene products that encode the N-terminal flanking peptides of preprocaerulein, preproxenopsin, and preprolevitide and so have been termed caerulein precursor-related fragments (CPRF-Ea, CPRF-Eb, and CPRF-Ec). The data suggest that there may be considerable polymorphism among specimens from different populations of the R. esculenta complex. It is proposed that the distribution and amino acid sequences of skin antimicrobial peptides may be useful markers for taxonomic classification of particular sub-populations and for an understanding of phylogenetic interrelationships.
| ISSN : | 0196-9781 |
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| Mesh Heading : | Amino Acid Sequence Animals Anti-Bacterial Agents Antimicrobial Cationic Peptides Candida albicans Chromatography, High Pressure Liquid Escherichia coli Microbial Sensitivity Tests Molecular Sequence Data Molecular Weight Protein Isoforms Proteins Rana esculenta Sequence Homology, Amino Acid Skin Spectrometry, Mass, Electrospray Ionization Staphylococcus aureus isolation & purification pharmacology analysis isolation & purification drug effects drug effects chemistry isolation & purification pharmacology isolation & purification pharmacology metabolism drug effects |
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| Mesh Heading Relevant : | Amphibian Proteins chemistry chemistry pharmacology chemistry chemistry |
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Antimicrobial peptides and protease inhibitors in the skin secretions of the crawfish frog, Rana areolata.
(2002)
Journal - Biochimica et biophysica acta (Netherlands )
Abstract :
The dorsal skin of the crawfish frog, Rana areolata, is associated with numerous prominent granular glands. Proteomic analysis of electrically stimulated skin secretions from these glands enabled the identification and characterization of eight peptides with antimicrobial and hemolytic activity belonging to the previously identified brevinin-1, temporin-1, palustrin-2, palustrin-3, esculentin-1 (two peptides), and ranatuerin-2 (two peptides) families. The primary structures of the peptides were consistent with a close phylogenetic relationship between R. areolata and the pickerel frog, Rana palustris. Three structurally related cationic, cysteine-containing peptides were identified that show sequence similarity to peptide Leucine-Arginine, a peptide with immunomodulatory and histamine-releasing properties from the skin of the northern leopard frog, Rana pipiens. The skin secretions contained a 61-amino-acid-residue peptide that inhibited porcine trypsin and possessed a 10-cysteine-residue motif that is characteristic of a protease inhibitor previously isolated from the parasitic nematode, Ascaris suum. A 48-amino-acid-residue protein containing eight cysteine residues in the whey acidic protein (WAP) motif, characteristic of elafin (skin-derived antileukoproteinase) and secretory leukocyte protease inhibitor, was also isolated. The data suggest that protease inhibitors in skin secretions may play a role complementary to cationic, amphipathic alpha-helical peptides in protecting anurans from invasions by microorganisms.
| ISSN : | 0006-3002 |
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| Mesh Heading : | Amino Acid Sequence Animals Anti-Infective Agents Antimicrobial Cationic Peptides Erythrocytes Hemolysis Humans Molecular Sequence Data Peptide Fragments Peptides Protease Inhibitors Skin isolation & purification pharmacology drug effects drug effects chemistry isolation & purification isolation & purification pharmacology pharmacology |
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| Mesh Heading Relevant : | Amphibian Proteins Ranidae analysis chemistry secretion analysis secretion |
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Antimicrobial peptides isolated from skin secretions of the diploid frog, Xenopus tropicalis (Pipidae).
(2001)
Journal - Biochimica et biophysica acta (Netherlands )
Abstract :
Seven peptides (XT-1-XT-7) with antimicrobial activity were isolated from norepinephrine-stimulated skin secretions of the diploid clawed frog, Xenopus tropicalis. Structural characterization of the peptides demonstrated that amino acid sequence similarity to antimicrobial peptides previously isolated from Xenopus laevis was low, suggesting that the species are not closely related phylogenetically. Peptides XT-5 and XT-3 are probably the orthologs of X. laevis peptide glycine-leucine amide (PGL(a)) and the N-terminal spacer region of prolevitide, respectively. XT-1, XT-6 and XT-7 show limited structural similarity to the spacer region of X. laevis procaeruleins and the paralogs XT-2 and XT-4 are similar to corresponding regions of proxenopsin. Orthologs of the magainins were not identified. The C-terminally alpha-amidated peptide XT-7 (GLLGPLLKIAAKVGSNLL.NH2) showed the lowest minimum inhibitory concentrations against reference microorganisms (Staphylococcus aureus 5 microM, Escherichia coli 5 microM, and Candida albicans 40 microM) and was also active against clinical isolates of methicillin-resistant S. aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus group C, Shigella sonnei, Pseudomonas aeruginosa and Enterobacter cloacae. The peptide was, however, hemolytic against human erythrocytes (50% lysis at 70 microM). Circular dichroism studies showed that XT-7 has a random structure in aqueous solution, pH 7.0 but adopts an alpha-helical conformation in the presence of 50% trifluoroethanol. Decreasing the cationicity of XT-7 either by replacement of the C-terminal CONH2 group by COOH or by deletion of the Lys(8) residue produced analogs with greatly (>10-fold) decreased antimicrobial potencies.
| ISSN : | 0006-3002 |
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| Mesh Heading : | Amino Acid Sequence Animals Anti-Bacterial Agents Anti-Infective Agents Candida albicans Circular Dichroism Erythrocytes Escherichia coli Hemolysis Humans Mass Spectrometry Microbial Sensitivity Tests Molecular Sequence Data Molecular Weight Norepinephrine Oligopeptides Skin Staphylococcus aureus Xenopus Xenopus Proteins drug effects drug effects drug effects pharmacology chemistry pharmacology chemistry drug effects drug effects chemistry pharmacology |
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| Mesh Heading Relevant : | isolation & purification isolation & purification secretion metabolism isolation & purification |
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