Motional Coherence in Fluid Phospholipid Membranes

Rheinstädter, Maikel C.; Das, Jhuma; Flenner, Elijah; Brüning, Beate-Annette; Seydel, Tilo; Kosztin, Ioan

doi:10.1103/physrevlett.101.248106

Cited by 49 publications

(51 citation statements)

References 21 publications

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“…The faster process can, therefore, be tentatively assigned to lipid motion confined to a certain area in the membrane. This observation is in agreement with recent results, which suggest that lipids move coherently in loosely bound clusters of ≈30Å diameter, rather than as independent molecules [9][10][11].…”

Section: Discussionsupporting

confidence: 83%

“…And ballistic lipid motion in fluid membranes has indeed been recently reported from quasielastic neutron scattering (QENS) using a neutron backscattering spectrometer [8]. Furthermore, it has been reported that lipids move coherently in loosely bound clusters, rather than as independent molecules [9][10][11]. A "hopping" diffusion of lipids into nearest neighbour sites was observed in single supported bilayers [12], and, recently, it has also been suggested that there is a flow-like component to the motion of the lipid molecules over long length scales [11].…”

Section: Introductionmentioning

confidence: 98%

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Incoherent Neutron Spin-Echo Spectroscopy as an Option to Study Long-Range Lipid Diffusion

et al. 2013

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Diffusion is the fundamental mechanism for lipids and other molecules to move in a membrane. It is an important process to consider in modelling the formation of membrane structures, such as rafts. Lipid diffusion is mainly studied by two different techniques: incoherent neutron scattering and fluorescence microscopy. Both techniques access distinctly different length scales. While neutron scattering measures diffusion over about 3 lipid diameters, microscopic techniques access motions of lipids over micrometer distances. The diffusion constants which are determined by these two methods often differ by about an order of magnitude, with the neutrons usually seeing a faster lipid diffusion. Different theories are used to describe lipid diffusion in the two experiments. In order to close the "gap" between these two techniques, we propose to study lipid diffusion at mesoscopic length scales using a neutron spin-echo (NSE) spectrometer. We have conducted an experiment in highly oriented, solid supported lipid bilayers to prove the feasibility of performing incoherent NSE on biological samples. Lateral lipid diffusion was measured in a fluid phase model membrane system at a length scale of 12Å. Using the high-energy resolution of the NSE technique, we find evidence for two dynamic processes.

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Section: Discussionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 98%

Incoherent Neutron Spin-Echo Spectroscopy as an Option to Study Long-Range Lipid Diffusion

et al. 2013

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“…For membranes, a shift of the main phase transition to higher temperatures with decreasing water content is already known for quite some time. 11 In recent years, neutron scattering studies of membrane dynamics focused on highly hydrated samples, [12][13][14][15] but only a few of these studies took hydration effects explicitly into consideration, e.g., König et al 14 In this work, we investigated the hydration influence on the dynamics of model membranes by quasielastic neutron scattering ͑QENS͒ and elastic incoherent neutron scattering. Model membrane systems such as 1,2-dimyristoyl-snglycero-3-phosphocholine ͑DMPC͒ show a similar thermodynamical behavior as real cell membranes 16 and are therefore often used to mimic their more complex natural counterparts.…”

Section: Introductionmentioning

confidence: 99%

Hydration dependent studies of highly aligned multilayer lipid membranes by neutron scattering

Trapp

Gutberlet

Jurányi

et al. 2010

The Journal of Chemical Physics

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We investigated molecular motions on a picoseconds timescale of 1,2-Dimyristoyl-snGlycero-3-Phosphocholine (DMPC) model membranes as a function of hydration by using elastic and quasielastic neutron scattering. Two different hydrations corresponding to approximately nine and twelve water molecules per lipid were studied, the latter being the fully hydrated state. In our study we focused on head group motions by using chain deuterated lipids. Information on in-plane and out-of-plane motions could be extracted by using solid supported DMPC multilayers. Our studies confirm and complete former investigations by K¨onig et al. and Rheinst¨adter et al. who describe the dynamics of lipidmembranes, but did not explore the influence of hydration on the head group dynamics as presented here. From the elastic data a clear shift of the main phase transition from the Pβ ripple phase to the Lα liquid phase was observed. A decreasing water content moves the transition temperature to higher temperatures. The quasielastic data permit a closer investigation of the different types of head group motion of the two samples. Two different model are needed to fit the elastic incoherent structure factor (EISF) and corresponding radii were calculated. Therefore the presented data show the strong influence hydration has on the head group mobility of DMPC. We investigated molecular motions on a picosecond timescale of 1,2-dimyristoylsn-glycero-3-phosphocholine ͑DMPC͒ model membranes as a function of hydration by using elastic and quasielastic neutron scattering. Two different hydrations corresponding to approximately nine and twelve water molecules per lipid were studied, the latter being the fully hydrated state. In our study, we focused on head group motions by using chain deuterated lipids. Information on in-plane and out-of-plane motions could be extracted by using solid supported DMPC multilayers. Our studies confirm and complete former investigations by König et al. ͓J. Phys. II ͑France͒ 2, 1589 ͑1992͔͒ and Rheinstädter et al. ͓Phys. Rev. Lett. 101, 248106 ͑2008͔͒ who described the dynamics of lipid membranes, but did not explore the influence of hydration on the head group dynamics as presented here. From the elastic data, a clear shift of the main phase transition from the P ␤ ripple phase to the L ␣ liquid phase was observed. Decreasing water content moves the transition temperature to higher temperatures. The quasielastic data permit a closer investigation of the different types of head group motion of the two samples. Two different models are needed to fit the elastic incoherent structure factor and corresponding radii were calculated. The presented data show the strong influence hydration has on the head group mobility of DMPC.

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“…In mammal organisms, vesicular membranes often serve as natural carriers. It is assumed that functional properties of a membrane depend likewise on its composition-dependent structure and dynamics [8,9]. In order to gain insight into membrane function, specific material properties, such as, e.g., the bilayer bending rigidity κ can be aimfully influenced.…”

mentioning

confidence: 99%

Perfluorooctanoic acid rigidifies a model lipid membrane

Brüning

Faragó

2014

Phys. Rev. E

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We report a combined dynamic light scattering and neutron spin-echo (NSE) study on vesicles composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine under the influence of varying amounts of perfluorooctanoic acid. We study local lipid bilayer undulations using NSE on time scales up to 200 ns. Similar to the effect evoked by cholesterol, we attribute the observed lipid bilayer stiffening to a condensing effect of the perfluorinated compound on the membrane. Perfluorinated compounds (PFCs) are fully fluorinated fatty acid analogs commonly used in a wide range of applications, such as the production of fire-extinguishing foams, anticorrosion agents, lubricants, or cosmetics [1,2]. As a consequence of their chemical stability, these compounds exhibit an environmental stability and are transmitted into the mammal food chain [3]. Due to their tendency to bioaccumulate, the compounds affect properties of cell membranes, causing developmental and reproductive disorders [2,4]. It is of particular interest to understand the effect of perfluorinated compounds not only on cellular membranes [5,6], but also on their biomimetic counterparts [7]. In mammal organisms, vesicular membranes often serve as natural carriers. It is assumed that functional properties of a membrane depend likewise on its composition-dependent structure and dynamics [8,9]. In order to gain insight into membrane function, specific material properties, such as, e.g., the bilayer bending rigidity κ can be aimfully influenced. Several studies have addressed the insertion of perfluorinated compounds into binary model membranes. Oriented mono-and bilayers were investigated by Matyszewska et al. using methods including surface pressure and potential measurements, infrared spectroscopy (IR), nuclear magnetic resonance (NMR) techniques, and molecular dynamics (MD) simulations [4,10,11]. While the phospholipid head group tilt against the bilayer normal decreases with rising amounts of inserted perfluorooctanoic acid (PFOA), the lipid acyl chain order increases. Lateral molecule diffusion in the membrane plane changes nonuniformly as the ratio of the components in the binary mixture is varied [10]. Lehmler et al. study liposomes containing binary mixtures of varying phospholipids and perfluorinated surfactants [12][13][14][15]. They use fluorescence spectroscopy and differential scanning calorimetry measurements to study the partitioning of surfactants into the phospholipid bilayer and find that it is independent of the lipid acyl chain length. While the phase behavior is largely independent of the type of phospholipid, PFOA itself is found to partition more readily into lipid bilayers in their fluid phase [13]. Several studies have taken advantage of a combination of dynamic light scattering (DLS) and long-wavelength NSE for the investigation of the local bilayer undulation dynamics in unilamellar lipid vesicles (ULVs) [16][17][18][19][20][21]. Here, we cover a window of more than 200 ns. The membrane dynamics was investigated by NSE using w...

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Motional Coherence in Fluid Phospholipid Membranes

Cited by 49 publications

References 21 publications

Incoherent Neutron Spin-Echo Spectroscopy as an Option to Study Long-Range Lipid Diffusion

Incoherent Neutron Spin-Echo Spectroscopy as an Option to Study Long-Range Lipid Diffusion

Hydration dependent studies of highly aligned multilayer lipid membranes by neutron scattering

Perfluorooctanoic acid rigidifies a model lipid membrane

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