ABSTRACT
The present study reports the structural characteristics, the biological activities, and preliminary clinical investigations of three synthetic members of the dermaseptin family of antimicrobial peptides. The three peptides showed similar tendencies to form alpha-helical structures in non-polar media. The antimicrobial activity towards bacteria and fungi was determined in the micromolar concentration and the peptides did not influenced peritoneal cells viability. One of the peptides was intravenously administered in mice at concentrations similar to those of antibiotics employed in bacterial/fungal infections and it did not cause any detectable changes in cells and tissues.
Subject(s)
Amphibian Proteins/chemistry , Amphibian Proteins/toxicity , Antimicrobial Cationic Peptides/chemistry , Antimicrobial Cationic Peptides/toxicity , Candida albicans/drug effects , Peritoneum/cytology , Streptococcus/drug effects , Amino Acid Sequence , Amphibian Proteins/metabolism , Animals , Antimicrobial Cationic Peptides/metabolism , Anura , Candida tropicalis/drug effects , Cell Survival/drug effects , Circular Dichroism , Dose-Response Relationship, Drug , Leukocyte Count , Mice , Microbial Sensitivity Tests , Molecular Sequence Data , Nocardia/drug effects , Protein Structure, Secondary , Staphylococcus aureus/drug effectsABSTRACT
Six new antimicrobial peptides structurally related to the dermaseptin family have been isolated from the skin secretion of the amphibian Phyllomedusa hypochondrialis. The primary structures of these molecules named as DShypo 01, 02, 03, 04, 06, and 07 were determined by de novo MS/MS experiments, Edman degradation, and cDNA sequencing. The fifth peptide was found to be precisely the same DS 01 from Phyllomedusa oreades previously described by our group. The majority of the peptides purified from the crude skin secretion could be directly localized and mapped onto a freshly dissected dorsal skin fragment using mass spectrometry-imaging techniques. Comparisons between peptides and commercial drugs on their antibacterial and anti-Leishmania amazonensis efficiencies, associated with peptide lytic effects on mammalian blood cells and surface plasmon resonance interaction studies on immobilized DMPC vesicles, were also performed.