title: A novel heterodimeric antimicrobial peptide from the tree-frog Phyllomedusa distincta.
abstract: We present here the purification and the analysis of the structural and functional properties of distinctin, a 5.4 kDa heterodimeric peptide with antimicrobial activity from the tree-frog Phyllomedusa distincta. This peptide was isolated from the crude extract of skin granular glands by different chromatographic steps. Its minimal inhibitory concentration was determined against pathogenic Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa strains. Amino acid sequencing and mass spectrometric investigations demonstrated that distinctin is constituted of two different polypeptide chains connected by an intermolecular disulphide bridge. Circular dichroism and Fourier-transformed infrared spectroscopy studies showed that this molecule adopts, in water, a structure containing a significant percentage of anti-parallel beta-sheet. A conformational variation was observed under experimental conditions mimicking a membrane-like environment. Database searches did not show sequence similarities with any known antimicrobial peptides. In the light of these results, we can consider distinctin as the first example of a new class of antimicrobial heterodimeric peptides from frog skin.
authors: Institute of Biology, University of Brasilia, Brazil.
authors: C V
authors: CV
authors: Batista
authors: A
authors: A
authors: Scaloni
authors: D J
authors: DJ
authors: Rigden
authors: L R
authors: LR
authors: Silva
authors: A
authors: A
authors: Rodrigues Romero
authors: R
authors: R
authors: Dukor
authors: A
authors: A
authors: Sebben
authors: F
authors: F
authors: Talamo
authors: C
authors: C
authors: Bloch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001001:Anura / Q000378:metabolism*; D002462:Cell Membrane; D002942:Circular Dichroism; D019281:Dimerization; D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D010455:Peptides