1-palmitoyl-2-oleoylglycero-3-phosphoserine and laurdan

Tailor-made ionic liquids based on imidazolium salts have recently attracted a large amount of attention because of their extraordinary properties and versatile functionality. An intriguing ability to interact with and stabilize membranes has already been reported for 1,3-dialkylimidazolium compounds. We now reveal further insights into the field by investigating 1,3-dimethyl-4,5-dialkylimidazolium (C

Topics: 2-Naphthylamine; Diphenylhexatriene; Fluorescent Dyes; Imidazoles; Ionic Liquids; Laurates; Lipid Bilayers; Models, Chemical; Molecular Structure; Phosphatidylcholines; Phosphatidylserines; Transition Temperature; Unilamellar Liposomes; Viscoelastic Substances

A time-dependent fluorescence shift method, biomimetic colorimetric assays, and molecular dynamics simulations have been performed in search of explanations why arginine rich peptides with intermediate lengths of about 10 amino acids translocate well through cellular membranes, while analogous lysine rich peptides do not. First, we demonstrate that an important factor for efficient peptide adsorption, as the first prerequisite for translocation across the membrane, is the presence of negatively charged phospholipids in the bilayer. Second, we observe a strong tendency of adsorbed arginine (but not lysine) containing peptides to aggregate at the bilayer surface. We suggest that this aggregation of oligoarginines leads to partial disruption of the bilayer integrity due to the accumulated large positive charge at its surface, which increases membrane-surface interactions due to the increased effective charge of the aggregates. As a result, membrane penetration and translocation of medium length oligoarginines becomes facilitated in comparison to single arginine and very long polyarginines, as well as to lysine containing peptides.

Topics: 2-Naphthylamine; Adsorption; Arginine; Biomimetics; Colorimetry; Dextrans; Fluorescence; Fluorescent Dyes; Laurates; Lipid Bilayers; Lysine; Membrane Potentials; Molecular Dynamics Simulation; Mycophenolic Acid; Peptides; Phosphatidylcholines; Phosphatidylserines; Phospholipids; Polyacetylene Polymer; Polymers; Polyynes