LAUSR

Abstract Lipid domains have been obtained using Langmuir-Blodgett films (LBs) and giant unilamellar vesicles (GUVs). Three membranes compositions were chosen, the canonical DOPC: DOPS (3:2)/SM/CHOL (1:1:1), the more physiological one: DOPC: DOPS (3:2)/SM/CHOL (2:1:1) and another one with more phospholipid content: DOPC: DOPS (3:2)/SM/CHOL (3:1:1). All systems were well characterized by π-A isotherms. As the (SM/CHOL (1:1:1)) concentration increases, the membrane fluidity decreases as demonstrated by the compressibility modulus and area per molecule values. Lipid domains morphology was examined by confocal microscopy. Images corroborated the presence of two liquid immiscible phases: a phospholipid-enriched L d phase and a sphingomyelin enriched L o phase. GBV-C peptide membrane interaction was examined using P6-2VIR576 peptide and tryptophan (Trp) fluorescence spectroscopy. P6-2VIR576 increased the fluidity of lipid monolayers and bilayers making hard to distinguish the L d /L o edges. Its capacity to inhibit the action of the fusion peptide of human immunodeficiency virus (HIV-1 FP) on membranes has been demonstrated.