Pivotal surfaces in inverse hexagonal and cubic phases of phospholipids and glycolipids

Marsh, Derek

doi:10.1016/j.chemphyslip.2010.12.010

Cited by 20 publications

(21 citation statements)

References 29 publications

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“…Supplemental Theory, with Continuum Modeling Methods, P2 1 Boundary Conditions, 22 equations, one table, two figures, and References (54)(55)(56)(57)(58)(59)(60)(61)(62) are available at http://www.biophysj.org/biophysj/supplemental/S0006-3495 (14) 00284-7.…”

Section: Supporting Materialsmentioning

confidence: 99%

Molecular Modeling of Lipid Membrane Curvature Induction by a Peptide: More than Simply Shape

Sodt

Pastor

2014

Biophysical Journal

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Molecular dynamics simulations of an amphipathic helix embedded in a lipid bilayer indicate that it will induce substantial positive curvature (e.g., a tube of diameter 20 nm at 16% surface coverage). The induction is twice that of a continuum model prediction that only considers the shape of the inclusion. The discrepancy is explained in terms of the additional presence of specific interactions described only by the molecular model. The conclusion that molecular shape alone is insufficient to quantitatively model curvature is supported by contrasting molecular and continuum models of lipids with large and small headgroups (choline and ethanolamine, respectively), and of the removal of a lipid tail (modeling a lyso-lipid). For the molecular model, curvature propensity is analyzed by computing the derivative of the free energy with respect to bending. The continuum model predicts that the inclusion will soften the bilayer near the headgroup region, an effect that may weaken curvature induction. The all-atom predictions are consistent with experimental observations of the degree of tubulation by amphipathic helices and variation of the free energy of binding to liposomes.

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Section: Supporting Materialsmentioning

confidence: 99%

Molecular Modeling of Lipid Membrane Curvature Induction by a Peptide: More than Simply Shape

Sodt

Pastor

2014

Biophysical Journal

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“…Bending Free Energy from Simulation must have a pivotal plane at which surface bending is not coupled to area compression/expansion (1,53). Moreover, the position of the pivotal plane specifies where the surface is defined and at which the mechanical constants are specified (2,37).…”

Section: Biophysical Journal 104(10) 2202-2211mentioning

confidence: 99%

Bending Free Energy from Simulation: Correspondence of Planar and Inverse Hexagonal Lipid Phases

Sodt

Pastor

2013

Biophysical Journal

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Simulations of two distinct systems, one a planar bilayer, the other the inverse hexagonal phase, indicate consistent mechanical properties and curvature preferences, with single DOPE leaflets having a spontaneous curvature, R0 = -26 Å (experimentally ~ -29.2 Å) and DOPC leaflets preferring to be approximately flat (R0= -65 Å, experimentally ~ -87.3 Å). Additionally, a well-defined pivotal plane, where a DOPE leaflet bends at constant area, has been determined to be near the glycerol region of the lipid, consistent with the experimentally predicted plane. By examining the curvature frustration of both high and low curvature, the transferability of experimentally determined bending constants is supported. The techniques herein can be applied to predict the effect of biologically active molecules on the mechanical properties of lipid bilayers under well-controlled conditions.

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“…The process of GMO ring construction is based on both experimental data and geometrical assumptions. [21][22][23] The most important parameters are the hexagonal lattice parameter of the H II mesophase, α, which is related to the lattice parameter d hex (Figure 1…”

Section: A Construction Of the Gmo Tubementioning

confidence: 99%

“…Therefore, we propose a technique for calculating the longitudinal structural parameter based on the area of the pivotal surface of GMO molecules. 23 Our second method suggests a formal initial state of water that allows taking into account the complex geometry of the GMO tube. Generally, it is a Monte Carlo rejection sampling routine, applied for filling the cylindrical-like volume of the GMO tube with water molecules.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics approach to water structure of HII mesophase of monoolein

Kolev

Ivanova

Madjarova

et al. 2012

The Journal of Chemical Physics

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The goal of the present work is to study theoretically the structure of water inside the water cylinder of the inverse hexagonal mesophase (H(II)) of glyceryl monooleate (monoolein, GMO), using the method of molecular dynamics. To simplify the computational model, a fixed structure of the GMO tube is maintained. The non-standard cylindrical geometry of the system required the development and application of a novel method for obtaining the starting distribution of water molecules. A predictor-corrector schema is employed for generation of the initial density of water. Molecular dynamics calculations are performed at constant volume and temperature (NVT ensemble) with 1D periodic boundary conditions applied. During the simulations the lipid structure is kept fixed, while the dynamics of water is unrestrained. Distribution of hydrogen bonds and density as well as radial distribution of water molecules across the water cylinder show the presence of water structure deep in the cylinder (about 6 Å below the GMO heads). The obtained results may help understanding the role of water structure in the processes of insertion of external molecules inside the GMO∕water system. The present work has a semi-quantitative character and it should be considered as the initial stage of more comprehensive future theoretical studies.

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Pivotal surfaces in inverse hexagonal and cubic phases of phospholipids and glycolipids

Cited by 20 publications

References 29 publications

Molecular Modeling of Lipid Membrane Curvature Induction by a Peptide: More than Simply Shape

Molecular Modeling of Lipid Membrane Curvature Induction by a Peptide: More than Simply Shape

Bending Free Energy from Simulation: Correspondence of Planar and Inverse Hexagonal Lipid Phases

Molecular dynamics approach to water structure of HII mesophase of monoolein

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