Modifiers of the Dipole Potential of Lipid Bilayers

This paper assesses the magnitude of change in the dipole potential (d) of membranes caused by the adsorption of modifiers on lipid bilayers of various compositions. We tested flavonoids, muscle relaxants, thyroid hormones, and xanthene and styrylpyridinium dyes in order to assess their dipole-modifying properties. A quantitative description of the modifying action of flavonoids, muscle relaxants, thyroid hormones, and xanthene dyes is shown as the ratio of the maximum change in the bilayer dipole potential upon saturation and the absolute d value of the unmodified membrane. The slopes of the linear relationship between the increase in the dipole potential of phospholipid bilayers and the concentration of styrylpyridinium dyes in membrane-bathing solutions were found. We described the relationships between the change in d and the chemical structure of modifiers, as well as the charge and spontaneous curvature of lipid monolayers.

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CRYO-Tem Measurements of Membrane Elasticity in Equilibrium Vesicle Systems: Two Distinct Mechanisms of Stability

Microscopy and Microanalysis ◽

10.1017/s1431927600036734 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 848-849

Author(s):

B. Coldren ◽

H.T. Jung ◽

J. Zasadzinski

Keyword(s):

Lipid Bilayers ◽

Spontaneous Curvature ◽

Aqueous Mixtures ◽

Membrane Elasticity ◽

Theoretical Concepts ◽

Curvature Energy ◽

Nanomaterials Synthesis ◽

Equilibrium Phases ◽

Image Position ◽

New Applications

Aqueous mixtures of oppositely charged surfactants spontaneously form equilibrium phases of unilamellar vesicles.1 The wide variety of surfactants that display this behavior allows control over vesicle charge, size, and polydispersity. This may be useful for new applications in drug delivery, nanomaterials synthesis, and as tests of theoretical concepts of membrane organization and interactions.A subtle competition between the entropy of mixing and the elastic properties of surfactant and lipid bilayers determines their phase behavior and morphology. The curvature energy per unit area of bilayer, fc, iswhere R1 and R2 are the principle radii of curvature, K is the curvature modulus, and is the saddle-splay modulus. The spontaneous curvature, l/ro, is nonzero only if there is asymmetry between the two sides of the bilayer.

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Effect of Trehalose and Sucrose on the Hydration and Dipole Potential of Lipid Bilayers

Biophysical Journal ◽

10.1016/s0006-3495(00)76789-0 ◽

2000 ◽

Vol 78 (5) ◽

pp. 2452-2458 ◽

Cited By ~ 113

Author(s):

M. del C. Luzardo ◽

F. Amalfa ◽

A.M. Nuñez ◽

S. Díaz ◽

A.C. Biondi de Lopez ◽

...

Keyword(s):

Lipid Bilayers ◽

Dipole Potential

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Theoretical and computational modeling of peptide-lipid bilayer interaction studied by dynamic force spectroscopy

10.32469/10355/76254 ◽

2019 ◽

Author(s):

◽

Milica Utjesanovic

Keyword(s):

Computational Modeling ◽

Lipid Bilayer ◽

Lipid Bilayers ◽

Lipid Membranes ◽

Lipid Membrane ◽

Conformational Dynamics ◽

Quantitative Description ◽

Md Simulations ◽

Dynamic Force ◽

Detachment Rate

This thesis consists of three interrelated theoretical and computational modeling projects that investigate different aspects of peptide-lipid membrane interactions. (1) A general theoretical approach is formulated for the quantitative description of the detachment force distribution, P(F), and the corresponding force dependent detachment rate, k(F), of a peptide from a lipid bilayer, by assuming that peptide detachment from lipid membranes occurs stochastically along a few dominant diffusive pathways. Besides providing a consistent interpretation of the experimental data, the new method also predicts that k(F) exhibits catch-bond behavior (when, counter intuitively, the detachment rate decreases with increasing force). (2) The proposed multiple detachment pathways method is tested and validated for a particular peptide (SecA2-11) interacting with both zwitterionic POPC lipid and polar E. Coli membranes. Furthermore, molecular dynamics (MD) simulations are used to explored the conformational dynamics of SecA2-11 during its interaction with both POPC and anionic POPG lipid bilayers. (3) Finally, MD simulations are used to explore the conformational dynamics and energetics of the peptide melittin (MWT) and its diastereomer (MD4) interacting with POPC and POPG lipid bilayers. The obtained results provide further insight into the role of secondary structure in peptide-lipid bilayer interactions.

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Local sensitivity analysis of the ‘Membrane shape equation’ derived from the Helfrich energy

10.1101/2020.05.26.117275 ◽

2020 ◽

Author(s):

P. Rangamani ◽

A. Behzadan ◽

M. Holst

Keyword(s):

Differential Equations ◽

Lipid Bilayers ◽

Numerical Study ◽

Membrane Vesicles ◽

Energy Functional ◽

Specific Model ◽

Model Systems ◽

Spontaneous Curvature ◽

Membrane Mechanics ◽

Curvature Term

AbstractThe Helfrich energy is commonly used to model the elastic bending energy of lipid bilayers in membrane mechanics. The governing differential equations for certain geometric characteristics of the shape of the membrane can be obtained by applying variational methods (minimization principles) to the Helfrich energy functional and are well-studied in the axisymmetric framework. However, the Helfrich energy functional and the resulting differential equations involve a number of parameters, and there is little explanation of the choice of parameters in the literature, particularly with respect to the choice of the “spontaneous curvature” term that appears in the functional. In this paper, we present a careful analytical and numerical study of certain aspects of parametric sensitivity of Helfrich’s model. Using simulations of specific model systems, we demonstrate the application of our scheme to the formation of spherical buds and pearled shapes in membrane vesicles.

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Local sensitivity analysis of the “membrane shape equation” derived from the Helfrich energy

Mathematics and Mechanics of Solids ◽

10.1177/1081286520953888 ◽

2020 ◽

pp. 108128652095388

Author(s):

P Rangamani ◽

A Behzadan ◽

M Holst

Keyword(s):

Differential Equations ◽

Lipid Bilayers ◽

Numerical Study ◽

Membrane Vesicles ◽

Energy Functional ◽

Specific Model ◽

Model Systems ◽

Spontaneous Curvature ◽

Membrane Mechanics ◽

Curvature Term

The Helfrich energy is commonly used to model the elastic bending energy of lipid bilayers in membrane mechanics. The governing differential equations for certain geometric characteristics of the shape of the membrane can be obtained by applying variational methods (minimization principles) to the Helfrich energy functional and are well studied in the axisymmetric framework. However, the Helfrich energy functional and the resulting differential equations involve a number of parameters, and there is little explanation of the choice of parameters in the literature, particularly with respect to the choice of the “spontaneous curvature” term that appears in the functional. In this paper, we present a careful analytical and numerical study of certain aspects of parametric sensitivity of Helfrich’s model. Using simulations of specific model systems, we demonstrate the application of our scheme to the formation of spherical buds and pearled shapes in membrane vesicles.

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