The effects of 2H2O on the phase transition of large unilamellar vesicle (LUV) suspensions as detected by ultrasound spectroscopy and electron spin resonance

Loralie, D.; Magin, Richard L.; Bačić, Goran; Dunn, F.

doi:10.1016/0005-2736(89)90126-0

Cited by 16 publications

(6 citation statements)

References 18 publications

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“…A large amount of literature exists on the use of DXSA nitroxides for the study of dynamic and structural characteristics of ordered systems such as biand multibilayers,38-41 membranes,38-43 and lyo-and thermothropic liquid crystals40, 44,45 and in dispersed systems such as micelles46,47 and vesicles. [48][49][50][51] The two probes 5-and 16-DXSA nitroxides were chosen in order to have the -NO paramagnetic unit in different regions, when inserted in an ordered aggregate.…”

Section: Resultsmentioning

confidence: 99%

Electron paramagnetic resonance lineshape analysis of small and large probes introduced into micellar aqueous solutions of ammonium pentadecafluorooctanoate

Ristori¹,

Martini²

1992

Langmuir

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Section: Resultsmentioning

confidence: 99%

Electron paramagnetic resonance lineshape analysis of small and large probes introduced into micellar aqueous solutions of ammonium pentadecafluorooctanoate

Ristori¹,

Martini²

1992

Langmuir

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“…Hence, the SG I −SG II transition of DODPC proceeds between two closely related lamellar phases whereas the P α −H II transition of DOPE is accompanied by a considerable deformation of the aggregates, i.e., a dramatic change of their morphology. It was shown that D 2 O slightly increases the gel-to-liquid-crystalline-phase transition temperature of PC and PE lipids at full hydration probably because of stronger hydrogen bonds that stabilize the gel state. − Contrarily, the transition temperature from the lamellar to the inverted hexagonal phase of lipids is significantly depressed up to about 5 K when H 2 O was exchanged by D 2 O . In this case, stronger hydrogen bonds between the PE headgroups can be assumed to increase the inverse curvature strain within the lipid monolayers.…”

Section: Discussionmentioning

confidence: 99%

Structural Aspects of Lyotropic Solvation-Induced Transitions in Phosphatidylcholine and Phosphatidylethanolamine Assemblies Revealed by Infrared Spectroscopy

Binder

Pohle

2000

J. Phys. Chem. B

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The hydration of two peculiar unsaturated lipids with phosphatidylethanolamine (PE) and phosphatidylcholine (PC) headgroups, namely dioctadecadienoyl PC (DODPC) and dioleoyl PE (DOPE), has been studied at room temperature by infrared (IR) spectroscopy including the linear dichroism. Oriented films of these lipids subjected to an atmosphere with definite values of relative humidity were investigated. The choice of DODPC and DOPE was motivated by their common property of undergoing a lyotropic phase transition, which, in each case, nearly exclusively affects the polar part of the lipid aggregates and is, thus, termed "solvationinduced" transition. The temperature-RH phase diagrams of both lipids were determined. The headgroups of both lipids form quasi-crystalline structures at small RH. The long axes of the PE and PC moieties orient essentially parallel with respect to the polar interface of the lipid aggregates. Model-based analyses of IR linear-dichroism data are consistent with the idea that about 8-12 DOPE molecules with disordered chains assemble within one cross-section layer of a ribbonlike phase, P R . Dry DODPC forms a subgel phase (SG I ) with all-trans acyl chains. At a critical water activity near 0.6, the molecular disorder in the polar region of the lipid aggregates increases distinctly. This "headgroup melting" reflects the solvation-induced transitions leading to the SG II and H II phases in DODPC and DOPE, respectively. Hydrogen-bonding specifics due to the polar parts of both lipids were probed by means of H f D exchange. Particularly stable H bonds are indicated to exist in dried DOPE.

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“…This can be interpreted as a decrease in membrane fluidity or an increase in water penetration. 9 Compared to the above-mentioned very small differences in the time-averaged properties, a much stronger water isotope effect was observed in time-resolved character of the interactions between solvent and lipid molecules. 6 H/D bonds between water and DPPC headgroups, water bridges between two DPPC molecules and even charge pairs between cholines and carbonyls are much more persistent when the solvent was D 2 O.…”

Section: Introductionmentioning

confidence: 92%

Effect of heavy water on phospholipid membranes: experimental confirmation of molecular dynamics simulations

Beranová

Humpolíčková

Sýkora

et al. 2012

Phys. Chem. Chem. Phys.

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Although there were experimental indications that phospholipid bilayers hydrated with D(2)O express different biophysical properties compared with hydration by ordinary H(2)O, a molecular concept for this behavior difference was only recently proposed by a molecular dynamics simulations study [T. Róg et al., J. Phys. Chem. B, 2009, 113, 2378-2387]. Here we attempt to verify those theoretical predictions by fluorescence measurements on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes. Specifically, we determine the water isotope effect on headgroup hydration and mobility, lateral lipid diffusion and lipid backbone packing. Time-dependent fluorescence shift experiments show significantly slower dynamics and lower hydration of the headgroup region for a bilayer hydrated with D(2)O, an observation in good agreement with the calculated predicted differences in duration of lipid-lipid and lipid-water bridges and extent of water penetration into the bilayer, respectively. The water isotope effect on the lipid order parameter of the bilayer core (measured by fluorescence anisotropy) and lateral diffusion of lipid molecules (determined by two-focus fluorescence correlation spectroscopy) is close to the experimental errors of the experiments, however also refers to slightly more rigid organization of phospholipid bilayers in heavy water. This study confirms the view that the water isotope effect can be particularly found in time-resolved physicochemical properties of the membrane. Together with the simulations our experiments provide a comprehensive, molecular view on the effect of D(2)O on phospholipid bilayers.

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The effects of 2H2O on the phase transition of large unilamellar vesicle (LUV) suspensions as detected by ultrasound spectroscopy and electron spin resonance

Cited by 16 publications

References 18 publications

Electron paramagnetic resonance lineshape analysis of small and large probes introduced into micellar aqueous solutions of ammonium pentadecafluorooctanoate

Electron paramagnetic resonance lineshape analysis of small and large probes introduced into micellar aqueous solutions of ammonium pentadecafluorooctanoate

Structural Aspects of Lyotropic Solvation-Induced Transitions in Phosphatidylcholine and Phosphatidylethanolamine Assemblies Revealed by Infrared Spectroscopy

Effect of heavy water on phospholipid membranes: experimental confirmation of molecular dynamics simulations

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