Publications by authors named "Sylvie Boichot"
Primary amphipathic cell-penetrating peptides transport cargoes across cell membranes with high efficiency and low lytic activity. These primary amphipathic peptides were previously shown to form aggregates or supramolecular structures in mixed lipid-peptide monolayers, but their behavior in lipid bilayers remains to be characterized. Using atomic force microscopy, we have examined the interactions of P(alpha), a primary amphipathic cell-penetrating peptide which remains alpha-helical whatever the environment, with dipalmitoylphosphatidylcholine (DPPC) bilayers.
View Article and Find Full Text PDFThe mesoscopic organization adopted by two primary amphipathic peptides, P(beta) and P(alpha), in Langmuir-Blodgett (LB) films made of either the pure peptide or peptide-phospholipid mixtures was examined by atomic force microscopy. P(beta), a potent cell-penetrating peptide (CPP), and P(alpha) mainly differ by their conformational states, predominantly a beta-sheet for P(beta) and an alpha-helix for P(alpha), as determined by Fourier transform infrared spectroscopy. LB films of pure peptide, transferred significantly below their collapse pressure, were characterized by the presence of supramolecular structures, globular aggregates for P(beta) and filaments for P(alpha), inserted into the monomolecular film.
View Article and Find Full Text PDFHuman calcitonin and its C-terminal fragment 9-32 (hCT(9-32)) administered in a spray translocate into respiratory nasal epithelium with an effect similar to intravenous injection. hCT(9-32) is an efficient carrier to transfer the green fluorescent protein into excised bovine nasal mucosa. To understand the translocation of hCT(9-32) across plasma membranes, we investigated its interactions with phospholipids and its interfacial structure using model lipid monolayers.
View Article and Find Full Text PDFArticle Synopsis
- Sphingomyelin (SM) is essential for creating lipid microdomains called rafts that are enriched in cholesterol (Chl) within cell membranes.
- Atomic force microscopy (AFM) was utilized to investigate the structure of SM microdomains in bilayers made from SM mixed with either dioleoylphosphatidylcholine (DOPC) or palmitoyl-oleoyl-phosphatidylcholine (POPC).
- The study revealed that the gel phase of SM domains can vary significantly in size and shape, leading to different structural behaviors based on whether the bilayers contain diunsaturated or mixed-saturated phosphatidylcholine, indicating the need for more research using the more physiologically relevant POPC.
Article Synopsis
- Researchers studied bilayers made from a mixture of two types of phosphatidylcholine (DOPC and DPPC) to see how a specific peptide interacts with membranes.
- Atomic force microscopy revealed that a fragment of human calcitonin (hCT (9-32)), either on its own or attached to a protein, forms aggregates in certain lipid phases depending on the presence of cholesterol.
- The findings suggest that hCT (9-32) is crucial for how the peptide-cargo complex is positioned in membranes and may destabilize membranes through a "carpet-like" mechanism to aid in its carrier function.