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Penetration of the Antimicrobial Peptide Dicynthaurin into Phospholipid Monolayers at the Liquid–Air Interface
Author(s) -
Bringezu Frank,
Majerowicz Monika,
Maltseva Elena,
Wen Shaoying,
Brezesinski Gerald,
Waring Alan J.
Publication year - 2007
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200600503
Subject(s) - monolayer , peptide , membrane , chemistry , adsorption , biophysics , phospholipid , phosphatidylglycerol , penetration (warfare) , protein secondary structure , crystallography , biochemistry , organic chemistry , phosphatidylcholine , operations research , engineering , biology
This work focuses on the adsorption kinetics of dicynthaurin with lipid monolayers, the effect of peptide adsorption on the structure of the lipid condensed chain lattice, peptide orientation and secondary structure in the adsorbed state. The studies with DPPG as model system revealed strong adsorption and massive incorporation of the peptide into the monolayer. Infrared reflection absorption spectroscopy (IRRAS) experiments showed that the secondary structure of the peptide is maintained upon adsorption. Specular X‐ray reflectivity showed the destabilization of the condensed phase of the pure lipid monolayer and revealed a tilted orientation of the long axis of the peptide helix of about 40° from the surface normal. Incorporation of the peptide was found to be pressure dependent, and at high pressure a “squeeze‐out” was observed; however, the peptide remained localized to the interface, as suggested by infrared data. These findings were supported by optical fluorescence microscopy measurements which showed the squeeze‐out of the peptide on water, but not under physiological conditions. The results suggest that dicynthaurin is able to adsorb to the phosphatidylglycerol‐rich inner cytoplasmic membrane of bacteria and alter membrane integrity. To identify and interact with membrane motifs that are characteristic of microbes, but which are absent in eukaryotic cells, might be an intrinsic ability of peptide antibiotics.