Surface Behaviour and Peptide-Lipid Interactions of the Antibiotic Peptides, Maculatin and Citropin

AMBROGGIO ERNESTO E.; BOWIE JOHN; SEPAROVIC FRANCES; FIDELIO GERARDO D.

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES

Año: 2004 vol. 1664 p. 31 - 31

0005-2736

p class="abstract">Surface behaviour of Maculatin 1.1 and Citropin 1.1 antibiotic peptides have been studied using the Langmuir monolayer technique in order to understand the peptide-membrane interaction proposed as critical for cellular lysis. Both peptides have a spontaneous adsorption at the air-water interface, reaching surface potentials similar to those obtained by direct spreading. Collapse pressures (Pi(c), stability to lateral compression), molecular areas at maximal packing and surface potentials (DeltaV) obtained from compression isotherms of both pure peptide monolayers are characteristic of peptides adopting mainly alpha-helical structure at the interface. The stability of Maculatin monolayers depended on the subphase and increased when pH was raised. In an alkaline environment, Maculatin exhibits a molecular reorganization showing a reproducible discontinuity in the Pi-A compression isotherm. Both peptides in lipid films with the zwitterionic palmitoyl-oleoyl-phosphatidy