The antibacterial peptide ceratotoxin A displays alamethicin-like behavior in lipid bilayers.
Ceratotoxin A (CtxA), a 36-residue alpha-helical cationic peptide isolated from the medfly Ceratitis capitata, exhibits strong antibacterial activity. To determine its mode of action against bacteria, we investigated the behavior of ceratotoxin A by incorporating it into planar lipid bilayers. Macroscopic and single channel conductance experiments showed that ceratotoxin A forms voltage-dependent ion channels in bilayers according to the barrel-stave model. The characteristics of the channel suggest that the C-terminal regions form bundles of five or six helices embedded in the membrane, such that the N-terminal moieties lie on the polar side of the lipid bilayer.
Saint
Nathalie
N
CBS, UMR 5048 CNRS, UMR 554 INSERM, Université de Montpellier 1, 29 rue de Navacelles, 34090 Montpellier, France.
Marri
Laura
L
Marchini
Daniela
D
Molle
Gérard
G
D000408:Alamethicin / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D033622:Ceratitis capitata; D004553:Electric Conductivity; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism
D000900:Anti-Bacterial Agents; D019476:Insect Proteins; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C082689:ceratotoxin A protein, Ceratitis capitata; D000408:Alamethicin; C017251:1,2-oleoylphosphatidylcholine; C028694:1-palmitoyl-2-oleoylphosphatidylcholine