Ethanol enhances collective dynamics of lipid membranes

Kaye, Martin D.; Schmalzl, K.; Nibali, Valeria Conti; Tarek, Mounir; Rheinstädter, Maikel C.

doi:10.1103/physreve.83.050907

Cited by 22 publications

(20 citation statements)

References 30 publications

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“…One should also note that at the molecular level, a dynamical protrusion of cholesterol across the midplane, i.e . between the apposed monolayers may occur as suggested by quasielastic neutron scattering (QENS) studies (Endress et al, 2002b; Kaye et al, 2011). Indeed the square-law functional dependence as first discussed (Brown, 1982) is a model-free correlation among the experimental observables, and it does not rest on any specific interpretation (Fig.…”

Section: Nuclear Spin Relaxation Reveals Multiscale Dynamics Of Membrmentioning

confidence: 98%

“…Attractive and repulsive forces for the membrane lipids entails both the polar headgroups and the non-polar moieties, and yield a substantial polymorphism with both lamellar and nonlamellar phases (Amazon and Feigenson, 2014; Brown, 1994; Feigenson, 2006, 2015; Gruner, 1989; Krepkiy et al, 2009; Phillips et al, 2009; Seddon, 1990; Seddon et al, 1997; van Meer et al, 2008; Zimmerberg and Gawrisch, 2006). Notably, the structural and dynamical properties of biomembranes are mediated by the lipid composition and interactions with the proteins, water, cholesterol, and surfactants (Brown and Chan, 2007; Coskun and Simons, 2011; Kaiser et al, 2009; Kaye et al, 2011; Kinnun et al, 2015; Leftin et al, 2014b; Mallikarjunaiah et al, 2011; Rheinstädter et al, 2004; Tyler et al, 2015). Membrane remodeling requires mesoscopic elastic deformations of the lipids (Kinnun et al, 2015) that can play a central role in biological functioning with regard to lipid-protein interactions, domain formation, and various nano- and microstructures implicated in key cellular functions (Brown, 1997; Brown, 2012; Liang et al, 2014; Soubias et al, 2014, 2015; Teague et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Cholesterol-induced suppression of membrane elastic fluctuations at the atomistic level

Molugu

Brown

2016

Chemistry and Physics of Lipids

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Applications of solid-state NMR spectroscopy for investigating the influences of lipid-cholesterol interactions on membrane fluctuations are reviewed in this paper. Emphasis is placed on understanding the energy landscapes and fluctuations at an emergent atomistic level. Solid-state 2H NMR spectroscopy directly measures residual quadrupolar couplings (RQCs) due to individual C–2H labeled segments of the lipid molecules. Moreover, residual dipolar couplings (RDCs) of 13C–1H bonds are obtained in separated local-field NMR spectroscopy. The distributions of RQC or RDC values give nearly complete profiles of the order parameters as a function of acyl segment position. Measured equilibrium properties of glycerophospholipids and sphingolipids including their binary and tertiary mixtures with cholesterol show unequal mixing associated with liquid-ordered domains. The entropic loss upon addition of cholesterol to sphingolipids is less than for glycerophospholipids and may drive the formation of lipid rafts. In addition relaxation time measurements enable one to study the molecular dynamics over a wide time-scale range. For 2H NMR the experimental spin-lattice (R1Z) relaxation rates follow a theoretical square-law dependence on segmental order parameters (SCD) due to collective slow dynamics over mesoscopic length scales. The functional dependence for the liquid-crystalline lipid membranes is indicative of viscoelastic properties as they emerge from atomistic-level interactions. A striking decrease in square-law slope upon addition of cholesterol denotes stiffening relative to the pure lipid bilayers that is diminished in the case of lanosterol. Measured equilibrium properties and relaxation rates infer opposite influences of cholesterol and detergents on collective dynamics and elasticity at an atomistic scale that potentially affects lipid raft formation in cellular membranes.

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Section: Nuclear Spin Relaxation Reveals Multiscale Dynamics Of Membrmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Cholesterol-induced suppression of membrane elastic fluctuations at the atomistic level

Molugu

Brown

2016

Chemistry and Physics of Lipids

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“…Finally, and perhaps most importantly, ethanol has been found to increase membrane permeability [20,24,25]. Experiments using X-ray or neutron scattering to probe molecular dynamics and structure are scarce [26][27][28][29], most likely due to experimental challenges.…”

Section: Partitioning Of Ethanol In Lipid Membranesmentioning

confidence: 98%

“…Two-dimensional data sets were collected to study molecular structure perpendicular to the solid supported membranes (out-of-plane, ) and parallel to the membranes (in-plane, || ). c) Reflectivity measurement for samples containing 3 mol % A [25][26][27][28][29][30][31][32][33][34][35] . Fourier transforms of the reflectivity data using the shown phases (inset) provides the electron density perpendicular to the membrane.…”

Section: Position Of Amyloid-peptides In Lipid Membranesmentioning

confidence: 99%

The Interaction of Bio-Molecules with Lipid Membranes Studied by X-ray Diffraction

Rheinstädter

Toppozini

Dies

2014

Zeitschrift Für Physikalische Chemie

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For the past 100 years, X-ray diffraction has been a powerful and indispensable tool to study the structure of matter. The challenge when studying molecular ordering in biological materials is their inherent disorder and strong fluctuations, which often suppress the formation of Bragg peaks. In the case of membranes, X-rays can detect molecules inside and confined between membranes. In this article we review examples to highlight the capabilities and accomplishments of X-ray scattering for the determination of membrane structure. X-ray diffraction gives quantitative information about partitioning of a small molecule, ethanol, in lipid bilayers. By taking amyloid-peptides as examples, it is demonstrated that the position of peptides in lipid membranes can be determined with high precision. Confinement between membranes can organize molecules, as is the case for a mono-nucleotide, adenosine monophosphate, and the resulting pattern might be important to understand the formation of short RNA strands. With new approaches and techniques, and the increasingly powerful and capable devices, X-ray diffraction will continue to be the work horse for the determination of molecular structure in biological materials.

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“…In previous studies, membranes were immersed in a water-ethanol solution to ensure a specific concentration of ethanol molecules in the bilayers [6,9,10]. High absorption and background in the neutron spectra is detected as a result of the large proportion of solvent.…”

Section: Sample Preparationmentioning

confidence: 99%

Diffusion in membranes: Toward a two-dimensional diffusion map

Toppozini

García-Sakai

Bewley

et al. 2015

EPJ Web of Conferences

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Abstract. For decades, quasi-elastic neutron scattering has been the prime tool for studying molecular diffusion in membranes over relevant nanometer distances. These experiments are essential to our current understanding of molecular dynamics of lipids, proteins and membrane-active molecules. Recently, we presented experimental evidence from X-ray diffraction and quasi-elastic neutron scattering demonstrating that ethanol enhances the permeability of membranes. At the QENS 2014/WINS 2014 conference we presented a novel technique to measure diffusion across membranes employing 2-dimensional quasielastic neutron scattering. We present results from our preliminary analysis of an experiment on the cold neutron multi-chopper spectrometer LET at ISIS, where we studied the self-diffusion of water molecules along lipid membranes and have the possibility of studying the diffusion in membranes. By preparing highly oriented membrane stacks and aligning them horizontally in the spectrometer, our aim is to distinguish between lateral and transmembrane diffusion. Diffusion may also be measured at different locations in the membranes, such as the water layer and the hydrocarbon membrane core. With a complete analysis of the data, 2-dimensional mapping will enable us to determine diffusion channels of water and ethanol molecules to quantitatively determine nanoscale membrane permeability.

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Ethanol enhances collective dynamics of lipid membranes

Cited by 22 publications

References 30 publications

Cholesterol-induced suppression of membrane elastic fluctuations at the atomistic level

Cholesterol-induced suppression of membrane elastic fluctuations at the atomistic level

The Interaction of Bio-Molecules with Lipid Membranes Studied by X-ray Diffraction

Diffusion in membranes: Toward a two-dimensional diffusion map

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