Antibacterial activity and pore-forming properties of ceratotoxins: a mechanism of action based on the barrel stave model

• Published in: Biochimica et biophysica acta 2004-12, Vol.1667 (2), p.148-156
• Main Authors: Bessin, Yannick, Saint, Nathalie, Marri, Laura, Marchini, Daniela, Molle, Gérard
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; Ceratitis capitata - chemistry; Conductance; Electric Conductivity; Erythrocytes - drug effects; Erythrocytes - physiology; Fish Proteins; Hemolysin Proteins - pharmacology; Humans; Insect Proteins - chemistry; Insect Proteins - isolation & purification; Insect Proteins - metabolism; Insect Proteins - pharmacology; Ion channel; Ion Channels - chemistry; Lipid bilayer; Lipid Bilayers - chemistry; Models, Chemical; Molecular Sequence Data; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins - chemistry; α-helical peptide
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2004.09.011

Ceratotoxins are α-helical cationic peptides isolated from the medfly Ceratitis capitata. These amphipathic peptides were found to display strong antibacterial activity and weak hemolytic activity. When reconstituted into planar lipid bilayers, ceratotoxins developed highly asymmetric I/ V curves under voltage ramps and formed, in single-channel experiments, well-defined voltage-dependent ion channels according to the barrel stave model. The antibacterial activity and pore-forming properties of these molecules were well correlated. Similar experiments performed with synthesized truncated fragments showed that the C-terminal domain of ceratotoxins is strongly implicated in the formation of helical bundles in the membrane whereas the largely cationic N-terminal region is likely to anchor ceratotoxins on the lipid surface.