An increasing number of human diseases has been shown to be linked aggregation and amyloid formation by intrinsically disordered proteins (IDPs). Amylin, amyloid-β, α-synuclein are, indeed, involved in type-II diabetes, Alzheimer's, Parkinson's, respectively. Despite the correlation toxicity these at early stages with membrane damage, molecular events underlying process is quite complex understand. In this study, we demonstrate crucial role free lipids lipid–protein complex, which enables an...

The human islet amyloid polypeptide (hIAPP) is the primary component in toxic deposits type-2 diabetes. hIAPP self-assembles to aggregates that permeabilize membranes and constitutes plaques. Uncovering mechanisms of self-assembly key understanding toxicity treatment. Although structurally similar, hIAPP's rat counterpart, (rIAPP), non-toxic. It has been a puzzle why these peptides behave so differently. We combined multiscale modelling theory explain drastically different dynamics rIAPP:...

Amyloidogenic proteins are involved in many diseases, including Alzheimer's, Parkinson's, and type II diabetes. These thought to be toxic for cells because of their abnormal interaction with the cell membrane. Simpler model membranes (LUVs) have been used study early steps membrane-protein interactions subsequent evolution. Phospholipid LUVs formed water solution establish a chemical equilibrium between self-assembled small amount phospholipids (CMC). Here, using both experimental molecular...

We report on the mechanism of membrane fusion mediated by polyethylene glycol (PEG) and Ca2+ means a coarse-grained molecular dynamics simulation approach. Our data provide detailed view role cations polymer in modulating interaction between negatively charged apposed membranes. The PEG chains cause reduction inter-lamellar distance an increase concentration divalent cations. When thermally driven fluctuations bring membranes at close contact, switch from cis to trans Ca2+-lipid complexes...

The protein transport inside a cell is complex phenomenon that goes through several difficult steps. facilitated requires sophisticated machineries involving assemblies. In this work, we developed diffusion-reaction model to simulate co-transport kinetics of proteins and lipids. We assume the following: (a) there always small lipid concentration order Critical Micellar Concentration (CMC) in equilibrium with membrane; (b) binding lipids modulates hydrophobicity complexes and, therefore,...

The mechanisms underlying the formation of extracellular amyloid plaques on neuronal membranes, a major hallmark Alzheimer's disease, are subject intense debate. Here we use multiscale simulations and analytical theory to unveil early steps spontaneous self-assembly membrane-embedded α-helical Aβ (1–40) peptides. Based simple model describing electrostatic repulsions among water-exposed charged residues, presence distorted structures called "frustrated helices" is predicted. Large scale (20...

Abstract Cationic polylysine promotes, under neutral conditions, the spontaneous aggregation of opposite charged ZnTPPS in water. Spectroscopic investigations evidence a different preorganization onto polypeptide matrix depending on chain length. Spinodal decomposition theory confined geometry is used to model this mechanism by considering time evolution homogeneous distribution randomly adsorbed particles (porphyrins) rodlike polyelectrolyte (polymer) variable length L.

We report a new interferometric technique to measure the electric charge at gas-liquid interface of bubble in liquid. The rests by buoyancy against an electrode, and alternating field excites its capillary oscillations. oscillation amplitude quadrupolar mode frequency is measured interferometer, it used evaluate charge. scales with square root interfacial tension -(3)/(2) power law as function radius. For bubbles millimeter diameter range pure water, negative radius, hence, giving constant...

We report that at very low initial bulk concentrations, a couple of hundred times below the critical micellar concentration (CMC), anionic surfactant sodium dodecyl sulfate (SDS) adsorbed air-water interface gas bubble cannot be removed, on time scale experiment (hours), when surrounding solution is gently replaced by pure water. Extremely sensitive interferometric measurements resonance frequency bubble-forced oscillations give precise access to monolayer. The bulk-interface dynamic...

.In this paper, we propose and validate a multiscale model for the description of particle diffusion in presence trapping boundaries. We start from drift-diffusion equation which drift term describes effect bubble traps is modeled by short-range potential with an attractive repulsive core. The interaction particles attracted surface simulated Lennard–Jones that simplifies capture due to hydrophobic properties ions. In our model, replaced suitable boundary condition derived mass conservation...

A temperature-dependent irreversible variation of the average aggregation number GM1 micelles, with no change in chemical structure molecule, has been observed by light and x-ray scattering. is an amphiphilic molecule biological origin, similar to phospholipids but extended headgroup, made up many sugar units. simple model developed describe experimental results. It assumes that polar headgroups monomers may exist two different stable conformations, each them a very energy, dependent on its...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal expansion and compressibility coefficients of phospholipid vesicles: experimental determination theoretical modelingAntonio. Raudino, Felice. Zuccarello, Carmelo. La Rosa, Giuseppe. BuemiCite this: J. Phys. Chem. 1990, 94, 10, 4217–4223Publication Date (Print):May 1, 1990Publication History Published online1 May 2002Published inissue 1 1990https://pubs.acs.org/doi/10.1021/j100373a063https://doi.org/10.1021/j100373a063research-articleACS...

Insight into the forces governing a system is essential for understanding its behavior and function. Thermodynamic investigations provide wealth of information that not, or hardly, available from other methods. This article reviews thermodynamic approaches assays to measure collective properties such as heat adsorption / emission volume variations. These methods can be successfully applied study lipid vesicles (liposomes) biological membranes. With respect instrumentation, differential...

Peptide- or protein-induced curvatures of lipid membranes may be studied in molecular dynamics (MD) simulations. In these, are usually modeled as infinitely extended bilayers by using periodic boundary conditions. However, the enforced periodicity results an underestimation bending power peptides, unless patch size is much larger than induced curvature radii. this letter, we propose a novel approach to evaluate given distribution and/or density peptides based on use flat open-edged patches....

We report measurements of the relaxation and resonance frequency forced oscillating bubbles covered by a layer surface-active molecules, anionic surfactant sodium dodecyl sulfate (SDS). Less systematic investigations have been also carried out on neutral cationic surfactants. A divergence viscous damping is observed at very low bulk concentration. Subtle variations in peak are measured. Bubble oscillations driven an electric field measured with sensitive interferometric technique. Results...

Both light-scattering and differential scanning calorimetry (DSC) measurements account for the existence of a dramatic thermal hysteresis effect occurring in micellar solutions gangliosides. Light-scattering reveal that mean aggregation number ganglioside micelles assumes different values depending on sample history, phenomenon completely disappears above well-defined temperature. On other side, DSC assess heat-capacity variation versus temperature system depends as well history sample....

Langmuir-Blodgett monolayers may show nanoscopic periodic patterns parallel and/or perpendicular to the transfer direction. The experimental findings are interpreted by a nonequilibrium model based on stability of surfactant concentration and film thickness coupled fluctuations near meniscus surfactant-covered receding thin film. In high low speed limits, fluid subphase thickness, respectively transfer, selected. A qualitative phase diagram shows how density manage pattern shape.

We present a theoretical model of two-component lipid membranes in close contact with polyelectrolyte solution. Fluid mixtures charged and neutral lipids as well oppositely polyelectrolytes were considered, the being allowed to redistribute themselves order maximize their interaction polymer. In dilute regime adsorption onto surfaces induces lateral phase separation lipids, which form clusters near polymer sites. On raising concentration semidilute (overlapping chains) solution forms...

Light scattering experiments show that micellar solutions of various gangliosides have a thermotropic behaviour which is irreversible with respect to temperature. Gangliosides, amphiphilic molecules biological origin, form micelles in solution decrease their average aggregation number upon heating. When critical temperature reached, any further cooling and heating cycle does not alter the size. This process, determined by denaturation ganglioside molecule, explained considering...