title: Functional characterisation of the 1-18 fragment of esculentin-1b, an antimicrobial peptide from Rana esculenta.
abstract: Esculentin-1 is a 46-amino acid residue peptide isolated from skin secretions of Rana esculenta, displaying the most potent antimicrobial activity among the bioactive molecules found in the secretion, with negligible effects on eukaryotic cell membranes. From skin secretions, the 19-46 fragment of esculentin-1, devoid of antibacterial activity, was also isolated. We studied in detail the activity of the N-terminal fragment (1-18) of esculentin-1 using a synthetic amidated analogue. The results show that this fragment is highly active against most bacterial and fungal species, although at a lower extent than the full-length peptide, being four-fold more potent against Phytophthora nicotianae. It has a reduced activity against human erythrocytes with respect to the full-length peptide. The killing curves in liquid medium are similar for the two molecules and the shorter peptide is able to increase the bacterial outer and inner membrane permeability. Overall these data indicate that the antimicrobial properties of esculentin-1 are exerted by its N-terminal 1-18 region and that the positively charged residue distribution as well as peptide length represent important determinants for cell selectivity.
authors.affiliation: Dipartimento di Scienze Biochimiche "A. Rossi Fanelli," Istituto Pasteur-Fondazione Cenci Bolognetti, Azienda Ospedale S. Andrea, Università "La Sapienza," Rome, Italy.
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Mangoni
authors.forename: Daniela
authors.initials: D
authors.lastname: Fiocco
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Mignogna
authors.forename: Donatella
authors.initials: D
authors.lastname: Barra
authors.forename: Maurizio
authors.initials: M
authors.lastname: Simmaco
mesh_terms: D029845:Amphibian Proteins / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology*; D011898:Ranidae
chemical_list: D029845:Amphibian Proteins; D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D010446:Peptide Fragments; C092874:esculentin protein, Rana esculenta