The effect of increasing membrane curvature on the phase transition and mixing behavior of a dimyristoyl-sn-glycero-3-phosphatidylcholine/ distearoyl-sn-glycero-3-phosphatidylcholine lipid mixture as studied by Fourier transform infrared spectroscopy and differential scanning calorimetry

Brumm, Thomas J.; Jørgensen, Kent; Mouritsen, Ole G.; Bayerl, Thomas M.

doi:10.1016/s0006-3495(96)79695-9

Cited by 89 publications

(73 citation statements)

References 15 publications

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“…Figure 5 depicts a schematic overview of the lipid‐phase order for both nanodiscs and liposomes. We found that the response of lipid dynamics to a temperature change crossing T m deviates in nanodiscs (Figure 5 C and D) from the classical picture found in liposomes in this study (Figure 5 A and B) and that reported in the literature 6, 33. Specifically, we observed that DMPC molecules in liposomes were in the gel phase below 20 °C and adopted a tilted position with respect to the bilayer normal,26, 42 with very tight packing (Figure 5 A).…”

Section: Resultssupporting

confidence: 46%

Lipid Internal Dynamics Probed in Nanodiscs

et al. 2017

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Nanodiscs offer a very promising tool to incorporate membrane proteins into native‐like lipid bilayers and an alternative to liposomes to maintain protein functions and protein–lipid interactions in a soluble nanoscale object. The activity of the incorporated membrane protein appears to be correlated to its dynamics in the lipid bilayer and by protein–lipid interactions. These two parameters depend on the lipid internal dynamics surrounded by the lipid‐encircling discoidal scaffold protein that might differ from more unrestricted lipid bilayers observed in vesicles or cellular extracts. A solid‐state NMR spectroscopy investigation of lipid internal dynamics and thermotropism in nanodiscs is reported. The gel‐to‐fluid phase transition is almost abolished for nanodiscs, which maintain lipid fluid properties for a large temperature range. The addition of cholesterol allows fine‐tuning of the internal bilayer dynamics by increasing chain ordering. Increased site‐specific order parameters along the acyl chain reflect a higher internal ordering in nanodiscs compared with liposomes at room temperature; this is induced by the scaffold protein, which restricts lipid diffusion in the nanodisc area.

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Section: Resultssupporting

confidence: 46%

Lipid Internal Dynamics Probed in Nanodiscs

et al. 2017

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“…In contrast, molecular dynamics (MD) simulations pointed to an increasing diffusion coefficient with increasing vesicles size with the highest value for planar bilayers (7). Other properties, such as fusion rate (18, 23), phase transition temperature (19,24,25), and elasticity (20), have been shown to vary for vesicles of different sizes.NMR studies can provide a great deal of information on bilayer dynamics and order parameters. They have been used to investigate the effect of vesicle curvature on the dynamics of lipid acyl chains.…”

mentioning

confidence: 99%

Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR vibrational echoes

Kel

Tamimi

Fayer

2014

Proc. Natl. Acad. Sci. U.S.A.

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The ultrafast structural dynamics inside the bilayers of dilauroylphosphatidylcholine (DLPC) and dipalmitoylphosphatidylcholine vesicles with 70, 90, and 125 nm diameters were directly measured with 2D IR vibrational echo spectroscopy. The antisymmetric CO stretch of tungsten hexacarbonyl was used as a vibrational probe and provided information on spectral diffusion (structural dynamics) in the alkyl region of the bilayers. Although the CO stretch absorption spectra remain the same, the interior structural dynamics become faster as the size of the vesicles decrease, with the size dependence greater for dipalmitoylphosphatidylcholine than for DLPC. As DLPC vesicles become larger, the interior dynamics approach those of the planar bilayer.vesicle bilayer dynamics | vesicle size dependent dynamics | vesicles chainlength dependent dynamics T he plasma membrane provides a boundary between a living cell and its surroundings and between cellular compartments, providing organizational control of proteins and small molecules that are critical for achieving the complexity of biological systems. In addition to a permeability barrier, the second role of the plasma membrane is serving as the solvent for membrane proteins and other biomolecules. The lipid environment of membrane proteins can influence their function (1-5), and so impact cell signaling, metabolism, growth, defense, and a myriad of other biological functions.Membranes have a bilayer structure where the nonpolar chains of the lipids form the interior of bilayer, with zwitterionic or ionic head groups at the interfaces with water. Artificial lipid bilayers are frequently used as models of cell membranes for investigation of membrane properties and in studies of transmembrane proteins. Although a good deal is known about the structure of artificial membranes (6-12) and orientational and translational diffusion of lipids and other molecules (7, 13-16), much less is known about the fast interior structural dynamics of the bilayers, which serve as the dynamic bath modes that can impact membrane processes.Unilamellar vesicles (ULVs) of different sizes, as well as multilamellar vesicles (MLVs), are used as model membranes owing to their ease of preparation and handling. It has been shown that their properties depend on the curvature (size) (8,9,13,(17)(18)(19)(20). Aligned planar multi-bilayers (21) are membrane models that do not have curvature, yet they are less attractive for routine use because they are substantially more difficult to prepare than vesicles.Numerous experiments have been performed to determine which type of model bilayers most closely represents the properties of the plasma membrane. However, no consensus exists because the results obtained by different methods and groups are not in agreement. Some small-angle X-ray scattering and small-angle neutron scattering (SANS) experiments indicate that the structural properties of ULVs and MLVs are curvature independent, the overall bilayer thickness does not dependent on vesicle size, and the thicknesses of...

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“…Experimentally it has been found that the heat capacity profiles of the lipid melting process are broadened for curved membranes (10,29). This broadening reflects that the work necessary to bend the membrane is temperature dependent (Fig.…”

Section: Modeling the Transition Behavior Between Two Membrane Segmentsmentioning

confidence: 95%

“…This thermodynamic reasoning is quite general and does not depend on the details of the Monte-Carlo simulations that are used for this illustration. One may equally well use experimental heat capacity profiles for differently curved systems (10,29). Nor does it depend on specific characteristics of the morphological change, or the origin of the osmotic driving force.…”

Section: Modeling the Transition Behavior Between Two Membrane Segmentsmentioning

confidence: 99%

Network formation of lipid membranes: Triggering structural transitions by chain melting

Schneider

Marsh

Jahn

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

121

130

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Phospholipids when dispersed in excess water generally form vesicular membrane structures. Cryo-transmission and freeze-fracture electron microscopy are combined here with calorimetry and viscometry to demonstrate the reversible conversion of phosphatidylglycerol aqueous vesicle suspensions to a three-dimensional structure that consists of extended bilayer networks. Thermodynamic analysis indicates that the structural transitions arise from two effects: (i) the enhanced membrane elasticity accompanying the lipid state fluctuations on chain melting and (ii) solventassociated interactions (including electrostatics) that favor a change in membrane curvature. The material properties of the hydrogels and their reversible formation offer the possibility of future applications, for example in drug delivery, the design of structural switches, or for understanding vesicle fusion or fission processes. Lipids may undergo a cooperative melting reaction linked to the loss in conformational order of the lipid chains (1). This transition is accompanied by a large change of the internal energy (or enthalpy) that can be studied by calorimetry. It has long been known that the melting profiles are influenced by secondary components, e.g., proteins (2), cholesterol, or anesthetics (3, 4). Phase diagrams of lipid mixtures usually are constructed as a function of the chemical potential of the components and the temperature (5). Another kind of possible transition involves changes in vesicular shape. These transitions have been studied in some detail by theoretical means, resulting in phase diagrams for vesicle structure as a function of the elastic constants (6, 7). Changes in these constants can explain theoretically the wealth of shapes of erythrocytes (8). There are therefore two kinds of phase diagrams found for lipid systems: one describing the calorimetric features of chain melting, mainly dependent on short-range cooperative events within the membrane plane, and the other describing transitions in shape and long-range order influenced by changes in the elastic constants.Although seemingly different features of a lipid system, the elastic constants and the heat capacity of the lipid membrane are related because they are coupled to thermodynamic fluctuations in the membrane properties (9). Maximum elasticity is achieved in the regime of ordered (gel)-fluid phase coexistence (10), which implies that close to the heat capacity maximum the elastic constants change markedly and as a consequence the membranes become more flexible. From this it is expected that changes in structural equilibria may be found close to the chain-melting transition.We demonstrate here thermodynamically how the structural changes couple to the chain melting. Large viscosity changes of dimyristoyl phosphatidylglycerol (DMPG) dispersions close to the calorimetric melting transition have been reported that are accompanied by marked changes in heat capacity, light scattering, and electrical conductance (11,12). The changes in viscosity suggest a change in the l...

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The effect of increasing membrane curvature on the phase transition and mixing behavior of a dimyristoyl-sn-glycero-3-phosphatidylcholine/ distearoyl-sn-glycero-3-phosphatidylcholine lipid mixture as studied by Fourier transform infrared spectroscopy and differential scanning calorimetry

Cited by 89 publications

References 15 publications

Lipid Internal Dynamics Probed in Nanodiscs

Lipid Internal Dynamics Probed in Nanodiscs

Size-dependent ultrafast structural dynamics inside phospholipid vesicle bilayers measured with 2D IR vibrational echoes

Network formation of lipid membranes: Triggering structural transitions by chain melting

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