Liposomes, Lipid Bilayers and Model Membranes

2014 ◽  
Keyword(s):  
Lipid Bilayers ◽  
Model Membranes

scholarly journals Interaction of the cellular prion protein with raft-like lipid membranes

2007 ◽  
Vol 388 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Kerstin Elfrink ◽  
Luitgard Nagel-Steger ◽  
Detlev Riesner
Keyword(s):  
Prion Protein ◽  
Lipid Bilayers ◽  
Analytical Ultracentrifugation ◽  
Chinese Hamster ◽  
Lipid Vesicles ◽  
Cellular Prion Protein ◽  
Model Membranes ◽  
Degree Of Saturation ◽  
Insertion Reaction ◽  
Chip Surface

Abstract Conversion of the cellular isoform of the prion protein (PrPC) into the disease-associated isoform (PrPSc) plays a key role in the development of prion diseases. Within its cellular pathway, PrPC undergoes several posttranslational modifications, i.e., the attachment of two N-linked glycans and a glycosyl phosphatidyl inositol (GPI) anchor, by which it is linked to the plasma membrane on the exterior cell surface. To study the interaction of PrPC with model membranes, we purified posttranslationally modified PrPC from transgenic Chinese hamster ovary (CHO) cells. The mono-, di- and oligomeric states of PrPC free in solution were analyzed by analytical ultracentrifugation. The interaction of PrPC with model membranes was studied using both lipid vesicles in solution and lipid bilayers bound to a chip surface. The equilibrium and mechanism of PrPC association with the model membranes were analyzed by surface plasmon resonance. Depending on the degree of saturation of binding sites, the concentration of PrPC released from the membrane into aqueous solution was estimated at between 10-9 and 10-7 M. This corresponds to a free energy of the insertion reaction of -48 kJ/mol. Consequences for the conversion of PrPC to PrPSc are discussed.

A small protein in model membranes: a time-resolved fluorescence and ESR study on the interaction of M13 coat protein with lipid bilayers

1992 ◽  
Vol 21 (5) ◽  
pp. 305-311 ◽  
Author(s):  
Johan C. Sanders ◽  
M. Francesca Ottaviani ◽  
Arie van Hoek ◽  
Antonie J. W. G. Visser ◽  
Marcus A. Hemminga
Keyword(s):  
Coat Protein ◽  
Lipid Bilayers ◽  
Model Membranes ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Small Protein

scholarly journals The Biosurfactant β-Aescin: A Review on the Physico-Chemical Properties and Its Interaction with Lipid Model Membranes and Langmuir Monolayers

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 117 ◽  
Author(s):  
Ramsia Geisler ◽  
Carina Dargel ◽  
Thomas Hellweg
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Phase State ◽  
Chemical Properties ◽  
Langmuir Monolayers ◽  
Model Membranes ◽  
Biologically Active ◽  
Horse Chestnut ◽  
Lipid Phase ◽  
Gel Phase

This review discusses recent progress in physicochemical understanding of the action of the saponin β -aescin (also called β -escin), the biologically active component in the seeds of the horse chestnut tree Aesculus hippocastanum. β -Aescin is used in pharmacological and cosmetic applications showing strong surface activity. In this review, we outline the most important findings describing the behavior of β -aescin in solution (e.g., critical micelle concentration ( c m c ) and micelle shape) and special physicochemical properties of adsorbed β -aescin monolayers at the air–water and oil–water interface. Such monolayers were found to posses very special viscoelastic properties. The presentation of the experimental findings is complemented by discussing recent molecular dynamics simulations. These simulations do not only quantify the predominant interactions in adsorbed monolayers but also highlight the different behavior of neutral and ionized β -aescin molecules. The review concludes on the interaction of β -aescin with phospholipid model membranes in the form of bilayers and Langmuir monolayers. The interaction of β -aescin with lipid bilayers was found to strongly depend on its c m c . At concentrations below the c m c , membrane parameters are modified whereas above the c m c , complete solubilization of the bilayers occurs, depending on lipid phase state and concentration. In the presence of gel-phase phospholipids, discoidal bicelles form; these are tunable in size by composition. The phase behavior of β -aescin with lipid membranes can also be modified by addition of other molecules such as cholesterol or drug molecules. The lipid phase state also determines the penetration rate of β -aescin molecules into lipid monolayers. The strongest interaction was always found in the presence of gel-phase phospholipid molecules.

scholarly journals A myelin sheath protein forming its lattice

2020 ◽  
Vol 295 (26) ◽  
pp. 8706-8707
Author(s):  
Hideaki Tsuge
Keyword(s):  
Escherichia Coli ◽  
Molecular Mechanism ◽  
Lipid Bilayers ◽  
Polar Lipid ◽  
Myelin Sheath ◽  
Three Dimensional ◽  
Model Membranes ◽  
Peripheral Myelin Protein ◽  
Dimensional Lattice ◽  
Open Question

The formation of a mature, multilayered myelin sheath requires the compaction of lipid bilayers, but the molecular mechanism by which these bilayers condense is an open question. In this issue, Ruskamo et al. find that peripheral myelin protein P2 forms an ordered three-dimensional lattice within model membranes using Escherichia coli polar lipid liposomes. These data will help to understand the assembly, function, and structure of the myelin sheath.

COMPUTER SIMULATIONS OF MEMBRANE-LYTIC PEPTIDES: PERSPECTIVES IN DRUG DESIGN

2007 ◽  
Vol 05 (02b) ◽  
pp. 611-626 ◽  
Author(s):  
ANTON A. POLYANSKY ◽  
PAVEL E. VOLYNSKY ◽  
ROMAN G. EFREMOV
Keyword(s):  
Lipid Bilayers ◽  
Contact Region ◽  
Membrane Surface ◽  
Sodium Dodecyl ◽  
Md Simulations ◽  
Model Membranes ◽  
Sodium Dodecyl Sulfate Micelle ◽  
Bacterial Membranes ◽  
Local Character ◽  
Lytic Peptides

Structure activity relationships were investigated for membrane-lytic peptides (MLP) Ltc1 and Ltc2a from the latarcin family. The peptides were studied via long-term molecular dynamics (MD) simulations in different membrane environments (detergent micelles, mixed lipid bilayers mimiking eukaryotic and bacterial membranes). The calculated structure of Ltc2a in sodium dodecyl sulfate micelle agrees well with the data obtained by 1H-NMR spectroscopy. This validates the applied modeling approach. The binding mode of MLPs is governed by several factors: (i) the membrane surface curvature; (ii) the conformational plasticity and hydrophobic organization of the peptide, which depend on the arrangement of charged, non-polar and helix-breaking residues in the amino acid sequence. In contrast to Ltc1, insertion of Ltc2a into model membranes induces significant changes in dynamic behavior of lipids in the contact region. Such a prominent membrane destabilization correlates with high membrane-lytic activity of Ltc2a. In all cases the "membrane response" has a local character and is caused by formation of specific peptide-lipid contacts. Results of MD simulations of Ltc2a in model membranes were used to develop a number of its analogs with predefined activity.

scholarly journals Chitosan derivatives targeting lipid bilayers: Synthesis, biological activity and interaction with model membranes

2018 ◽  
Vol 181 ◽  
pp. 1213-1223 ◽  
Author(s):  
Danubia Batista Martins ◽  
Fábio Domingues Nasário ◽  
Laiz Costa Silva-Gonçalves ◽  
Vera Aparecida de Oliveira Tiera ◽  
Manoel Arcisio-Miranda ◽  
...  
Keyword(s):  
Biological Activity ◽  
Lipid Bilayers ◽  
Model Membranes ◽  
Chitosan Derivatives
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