Temporin L: antimicrobial, haemolytic and cytotoxic activities, and effects on membrane permeabilization in lipid vesicles.
The temporins are a family of small, linear antibiotic peptides with intriguing biological properties. We investigated the antibacterial, haemolytic and cytotoxic activities of temporin L (FVQWFSKFLGRIL-NH2), isolated from the skin of the European red frog Rana temporaria. The peptide displayed the highest activity of temporins studied to date, against both human erythrocytes and bacterial and fungal strains. At variance with other known temporins, which are mainly active against Gram-positive bacteria, temporin L was also active against Gram-negative strains such as Pseudomonas aeruginosa A.T.C.C. 15692 and Escherichia coli D21 at concentrations comparable with those that are microbiocidal to Gram-positive bacteria. In addition, temporin L was cytotoxic to three different human tumour cell lines (Hut-78, K-562 and U-937), causing a necrosis-like cell death, although sensitivity to the peptide varied markedly with the specific cell line tested. A study of the interaction of temporin L with liposomes of different lipid compositions revealed that the peptide causes perturbation of bilayer integrity of both neutral and negatively charged membranes, as revealed by the release of a vesicle-encapsulated fluorescent marker, and that the action of the peptide is modulated to some extent by membrane lipid composition. In particular, the presence of negatively charged lipids in the model bilayer inhibits the lytic power of temporin L. We also show that the release of fluorescent markers caused by temporin L is size-dependent and that the peptide does not have a detergent-like effect on the membrane, suggesting that perturbation of bilayer organization takes place on a local scale, i.e. through the formation of pore-like openings.
Cattedra di Chimica Biologica, Dipartimento di Scienze Mediche Internistiche, Università di Cagliari, I-09042 Monserrato (CA), Italy. rinaldi@unica.it
Andrea C
AC
Rinaldi
Maria Luisa
ML
Mangoni
Anna
A
Rufo
Carla
C
Luzi
Donatella
D
Barra
Hongxia
H
Zhao
Paavo K J
PK
Kinnunen
Argante
A
Bozzi
Antonio
A
Di Giulio
Maurizio
M
Simmaco
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D003902:Detergents / Q000737:chemistry; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D020014:K562 Cells; D010455:Peptides; D011898:Ranidae / Q000378:metabolism*; D022161:Transport Vesicles / Q000187:drug effects; D014407:Tumor Cells, Cultured; D020298:U937 Cells
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D000970:Antineoplastic Agents; D003902:Detergents; D010455:Peptides; C469676:temporin L, Rana temporaria