We have investigated the pathway by which unilamellar POPC liposomes upon adsorption undergo rupture and form a supported lipid bilayer (SLB) on a SiO(2) surface. Biotinylated lipids were selectively incorporated in the outer monolayer of POPC liposomes to create liposomes with asymmetric lipid compositions in the outer and inner leaflets. The specific binding of neutravidin and anti-biotin to ...

Phosphatidylcholine/sphingomyelin/cholesterol (PC/SM/CHOL) ternary mixtures were investigated using differential scanning calorimetry (DSC). Palmitoyl-oleoyl phosphatidylcholine (POPC) and palmitoyl-docosahexaenoyl (-3) phosphatidylcholine (PDPC) were used to study the effect of the number of double bonds at the sn-2 position in PC molecule on the phase behavior of PC/SM/CHOL mixtures. The PDP...

Cell membranes show complex behavior, in part because of the large number of different components that interact with each other in different ways. One aspect of this complex behavior is lateral organization of components on a range of spatial scales. We found that lipid-only mixtures can model the range of size scales, from approximately 2 nm up to microns. Furthermore, the size of compositiona...

The purpose of this short communication was to examine whether the formation of a supported lipid bilayer (SLB) made with purely synthetic lipid or with Escherichia coli complex lipid may have any influence on the production and incorporation of the transmembrane protein α-hemolysin from Staphylococcus. Different molar ratio of E. coli total extract lipid and synthetic 1-palmitoyl-2-oleoyl-sn-g...

T-20 and T-1249 fusion inhibitor peptides were shown to interact with 1-palmitoyl-2-oleyl-phosphatidylcholine (POPC) (liquid disordered, ld) and POPC/cholesterol (1:1) (POPC/Chol) (liquid ordered, lo) bilayers, and they do so to different extents. Although they both possess a tryptophan-rich domain (TRD), T-20 lacks a pocket binding domain (PBD), which is present in T-1249. It has been postulat...

BACKGROUND In several neurodegenerative diseases, hyperphosphorylation at position Ser129 is found in fibrillar deposits of alpha-synuclein (asyn), implying a pathophysiological role of asyn phosphorylation in neurodegeneration. However, recent animal models applying asyn phosphorylation mimics demonstrated a protective effect of phosphorylation. Since metal-ion induced asyn oligomers were iden...

A 28-mer gammaM4 peptide, obtained by solid-state synthesis and corresponding to the fourth transmembrane segment of the nicotinic acetylcholine receptor gamma-subunit, possesses a single tryptophan residue (Trp453), making it an excellent model for studying peptide-lipid interactions in membranes by fluorescence spectroscopy. The gammaM4 peptide was reconstituted with synthetic lipids (vesicle...

Lateral diffusion of phospholipids is a process essential to membrane function, and can be measured by nuclear magnetic resonance (NMR). This project will use CODEX (Centerband-Only Detection of Exchange), the most highly-evolved NMR experiment combining magic angle spinning with exchange sensitivity, to measure lateral diffusion. P CODEX NMR measurements were performed on phospholipids in smal...

In this study we have prepared ceramide phosphoserine (CerPS) and examined its sterol-interacting properties. CerPS is a hydrogen-bonding sphingolipid, but its head group differs from that found in sphingomyelin (SM). Based on diphenylhexatriene steady-state anisotropy measurements, we observed that fully hydrated N-palmitoyl CerPS had a gel-to-liquid crystalline phase transition temperature of...

The idea that amphotericin B (AmB) may not require sterols to form ion selective channels has recently been criticized on the grounds that egg phospholipids commonly used in experiments may contain small amounts of sterol which associate with AmB to form AmB/sterol pore channel structures. It was recently shown in this laboratory that modest osmotic stress can enhance the formation of AmB chann...