Solid-supported lipid bilayers are useful model systems for mimicking cellular membranes; however, the interaction of the bilayer with the surface can disrupt the function of integral membrane proteins and impede topological transformations such as membrane fusion. As a result, a variety of tethered or cushioned lipid bilayer architectures have been described, which retain the proximity to the ...

The mechanism of voltage gating in K+ channels is controversial. The paddle model posits that highly charged voltage-sensor domains move relatively freely across the lipid bilayer in response to membrane depolarization; competing models picture the charged S4 voltage-sensor helix as being shielded from lipid contact by other parts of the protein. We measured the apparent free energy of membrane...

Recent toxicology studies suggest that nanosized aggregates of fullerene molecules can enter cells and alter their functions, and also cross the blood-brain barrier. However, the mechanisms by which fullerenes penetrate and disrupt cell membranes are still poorly understood. Here we use computer simulations to explore the translocation of fullerene clusters through a model lipid membrane and th...

Stably folded membrane proteins reside in a free energy minimum determined by the interactions of the peptide chains with each other, the lipid bilayer hydrocarbon core, the bilayer interface, and with water. The prediction of three-dimensional structure from sequence requires a detailed understanding of these interactions. Progress toward this objective is summarized in this review by means of...

The aggregation of human islet amyloid polypeptide (hIAPP or amylin) is associated with the pathogenesis of type 2 diabetes mellitus. Increasing evidence suggests that the interaction of hIAPP with β-cell membranes plays a crucial role in cytotoxicity. However, the hIAPP-lipid interaction and subsequent membrane perturbation is not well understood at atomic level. In this study, as a first step...

Introduction: Recent studies have shown the presence of Cl- channels in heart and liver mitochondrial membranes. In this work, we have characterized the functional profile of a Cl- channel from rat brain mitochondria. Methods: After removing and homogenizing the rat brain, the supernatant was separately centrifuged in MSEdigitonin, H2O and Na2CO3 and mitochondrial inner membrane vesicles wer...

Fluidity is essential for many biological membrane functions. The basis for understanding membrane structure remains the classic Singer-Nicolson model, in which proteins are embedded within a fluid lipid bilayer and able to diffuse laterally within a sea of lipid. Here we report lipid and protein diffusion in the plasma membrane of live cells of the bacterium Escherichia coli, using Fluorescenc...

The binding of the exchangeable apolipoprotein apolipophorin III (apoLp-III) to an egg phosphatidylcholine bilayer as a function of the concentration of diacylglycerol (DG) in the bilayer was studied by surface plasmon resonance spectroscopy. At a DG concentration of 2 mol % in the bilayer, the binding of apoLp-III reached saturation. Under saturating conditions, apoLp-III forms a closely packe...

A low pH method of liposome-membrane fusion (Schneider et al., 1980, Proc. Natl. Acad. Sci. U. S. A. 77:442) was used to enrich the mitochondrial inner membrane lipid bilayer 30-700% with exogenous phospholipid and cholesterol. By varying the phospholipid-to-cholesterol ratio of the liposomes it was possible to incorporate specific amounts of cholesterol (up to 44 mol %) into the inner membrane...

Depth of bilayer penetration and effects on lipid mobility conferred by the membrane-active peptides magainin, melittin, and a hydrophobic helical sequence KKA(LA)7KK (denoted KAL), were investigated by colorimetric and time-resolved fluorescence techniques in biomimetic phospholipid/poly(diacetylene) vesicles. The experiments demonstrated that the extent of bilayer permeation and peptide local...