Structure and Elasticity of Lipid Membranes with Genistein and Daidzein Bioflavinoids Using X-ray Scattering and MD Simulations

Raghunathan, Mohit; Zubovski, Yuriy; Venable, Richard M.; Pastor, Richard W.; Nagle, John F.; Tristram-Nagle, Stephanie

doi:10.1021/jp211904j

Cited by 59 publications

(70 citation statements)

References 46 publications

(100 reference statements)

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“…Volumes of lipid mixtures with and without peptides in fully hydrated multilamellar vesicles (MLV) were determined at 37±0.01 °C using an Anton-Paar USA DMA5000M (Ashland, VA) vibrating tube densimeter [47]. …”

Section: Methodsmentioning

confidence: 99%

HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD simulations

Akabori

Huang

Treece

et al. 2014

Biochimica et Biophysica Acta (BBA) - Biomembranes

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We report the effect on lipid bilayers of the Tat peptide Y47GRKKRRQRRR57 from the HIV-1 virus transactivator of transcription (Tat) protein. Synergistic use of low-angle X-ray scattering (LAXS) and atomistic molecular dynamics simulations (MD) indicate Tat peptide binding to neutral dioleoylphosphocholine (DOPC) lipid headgroups. This binding induced the local lipid phosphate groups to move 3 Å closer to the center of the bilayer. Many of the positively charged guanidinium components of the arginines were as close to the center of the bilayer as the locally thinned lipid phosphate groups. LAXS data for DOPC, DOPC/dioleoylphosphoethanolamine (DOPE), DOPC/dioleoylphosphoserine (DOPS), and a mimic of the nuclear membrane gave similar results. Generally, the Tat peptide decreased the bilayer bending modulus KC and increased the area/lipid. Further indications that Tat softens a membrane, thereby facilitating translocation, were provided by wide-angle X-ray scattering (WAXS) and neutron scattering. CD spectroscopy was also applied to further characterize Tat/membrane interactions. Although a mechanism for translocation remains obscure, this study suggests that the peptide/lipid interaction makes the Tat peptide poised to translocate from the headgroup region.

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Section: Methodsmentioning

confidence: 99%

HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD simulations

Akabori

Huang

Treece

et al. 2014

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…Volumes of fully hydrated MLVs of DMPC/TMCL lipid mixtures and pure lipids were determined as a function of temperature from 20±0.01°C to 55±0.01°C using an Anton-Paar USA DMA5000M (Ashland, VA) vibrating tube densimeter (Raghunathan et al, 2012). After densimetry, TLC revealed ~2% lysolecithin.…”

Section: Methodsmentioning

confidence: 99%

X-ray structure, thermodynamics, elastic properties and MD simulations of cardiolipin/dimyristoylphosphatidylcholine mixed membranes

Boscia

Treece

Mohammadyani

et al. 2014

Chemistry and Physics of Lipids

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Cardiolipins (CLs) are important biologically for their unique role in biomembranes that couple phosphorylation and electron transport like bacterial plasma membranes, chromatophores, chloroplasts and mitochondria. CLs are often tightly coupled to proteins involved in oxidative phosphorylation. The first step in understanding the interaction of CL with proteins is to obtain the pure CL structure, and the structure of mixtures of CL with other lipids. In this work we use a variety of techniques to characterize the fluid phase structure, material properties and thermodynamics of mixtures of dimyristoylphosphatidylcholine (DMPC) with tetramyristoylcardiolipin (TMCL), both with 14-carbon chains, at several mole percentages. X-ray diffuse scattering was used to determine structure, including bilayer thickness and area/lipid, the bending modulus, KC, and Sxray, a measure of chain orientational order. Our results reveal that TMCL thickens DMPC bilayers at all mole percentages, with a total increase of ~6 Å in pure TMCL, and increases AL from 64 Å2 (DMPC at 35°C) to 109 Å2 (TMCL at 50°C). KC increases by ~50%, indicating that TMCL stiffens DMPC membranes. TMCL also orders DMPC chains by a factor of ~2 for pure TMCL. Coarse grain molecular dynamics simulations confirm the experimental thickening of 2 Å for 20 mol% TMCL and locate the TMCL headgroups near the glycerol-carbonyl region of DMPC; i.e., they are sequestered below the DMPC phosphocholine headgroup. Our results suggest that TMCL plays a role similar to cholesterol in that it thickens and stiffens DMPC membranes, orders chains, and is positioned under the umbrella of the PC headgroup. CL may be necessary for hydrophobic matching to inner mitochondrial membrane proteins. Differential scanning calorimetry, Sxray and CGMD simulations all suggest that TMCL does not form domains within the DMPC bilayers. We also determined the gel phase structure of TMCL, which surprisingly displays diffuse X-ray scattering, like a fluid phase lipid. AL = 40.8 Å2 for the ½TMCL gel phase, smaller than the DMPC gel phase with AL = 47.2 Å2, but similar to AL of DLPE = 41 Å2, consistent with untilted chains in gel phase TMCL.

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“…The sample was typically held at 10°C overnight until the next heat/cool cycle began the following day. Conversion of raw densities ρ s into lipid molecular volumes V L used the equation 9 …”

Section: Methodsmentioning

confidence: 99%

Volumetric stability of lipid bilayers

Hallinen

Tristram-Nagle

Nagle

2012

Phys. Chem. Chem. Phys.

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In agreement with recent reports, a commercial densimeter has yielded a gradual decrease in lipid molecular volume of DPPC multilamellar vesicle dispersions in the gel phase upon repeated thermal cycling between 10ºC and 50ºC. The considerable size of this decrease would have significant implications for the physical chemistry of biomembranes. In contrast, neutral buoyancy measurements performed with similar thermal cycling indicate no gradual change in lipid volume in the gel phase at 20ºC. Remixing the lipid in the densimeter shows that the apparent volume decrease is an artifact. We conclude that gel phase DPPC bilayers exist in a volumetrically stable phase.

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Structure and Elasticity of Lipid Membranes with Genistein and Daidzein Bioflavinoids Using X-ray Scattering and MD Simulations

Cited by 59 publications

References 46 publications

HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD simulations

HIV-1 Tat membrane interactions probed using X-ray and neutron scattering, CD spectroscopy and MD simulations

X-ray structure, thermodynamics, elastic properties and MD simulations of cardiolipin/dimyristoylphosphatidylcholine mixed membranes

Volumetric stability of lipid bilayers

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