Low hydration phase properties of phospholipid mixtures

Bryant, Gary; Pope, J. H.; Wolfe, Joe

doi:10.1007/bf00196767

Cited by 30 publications

(25 citation statements)

References 38 publications

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“…The other spectral component consists of an intense isotropic resonance of 400 Hz width, classically interpreted as excess free water or as small water domains trapped in the membrane. 30 In the presence of RCD, the isotropic resonance was broadened (500 Hz) and its increased relative contribution to the spectrum led to a poorly resolved line shape profile. As a direct consequence, the doublet lines were overlapped and a precise measurement was no more possible ( Figure 3B, bottom).…”

Section: H-nmr Spectroscopy Of H O-hydratedmentioning

confidence: 98%

Mechanism of α-Cyclodextrin-lnduced Hemolysis. 1. The Two-Step Extraction of Phosphatidylinositol from the Membrane

Fauvelle

Debouzy

Crouzy

et al. 1997

Journal of Pharmaceutical Sciences

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It has been suggested that the interaction of cyclodextrins with the lipid components of the erythrocyte membranes is the determining factor in the hemolysis induced by these cyclic oligosaccharides. In the case of alpha-cyclodextrin (cyclomaltohexose), phospholipids have been identified as the cell target. In our study, evidence for the interaction between alpha-cyclodextrin and different phospholipids has been obtained using synthetic membranes. Since phosphatidylinositol (PI) showed the strongest affinity for alpha-cyclodextrin, it has been selected to investigate the respective contributions of the polar head group and the aliphatic chains to the association process using 31P, 2H, and 1H NMR spectroscopy. In this work, we describe the two-step extraction of PI from the membrane following its association with alphaCD: a cyclodextrin molecule is first attracted to the membrane surface by electrostatic remote interactions and associates with the lipid head group. Then the whole PI molecule is extracted, and inclusion of its unsaturated sn-2 acyl chain into another alphaCD molecule occurs in the bulk.

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Section: H-nmr Spectroscopy Of H O-hydratedmentioning

confidence: 98%

Mechanism of α-Cyclodextrin-lnduced Hemolysis. 1. The Two-Step Extraction of Phosphatidylinositol from the Membrane

Fauvelle

Debouzy

Crouzy

et al. 1997

Journal of Pharmaceutical Sciences

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“…Bryant et al used 2 H NMR to investigate the reduction in spectral splitting of the deuterium spectra of D 2 O/phospholipid systems for POPC and POPE near the main phase transition. 23 For POPC the splitting intensities were stable above and below the phase transition, but dropped to zero at or near the phase transition. For POPE, similar splitting intensities were observed; however, the intensities became unstable near the main phase transition, corresponding a temperature range of 20 deg.…”

Section: Introductionmentioning

confidence: 96%

Molecular Characterization of Gel and Liquid-Crystalline Structures of Fully Hydrated POPC and POPE Bilayers

2007

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Molecular dynamics simulations were used for a comprehensive study of the structural properties of monounsaturated POPC and POPE bilayers in the gel and liquid-crystalline state at a number of temperatures, ranging from 250 to 330 K. Though the chemical structures of POPC and POPE are largely similar (choline versus ethanolamine headgroup), their transformation processes from a gel to a liquid-crystalline state are contrasting. In the similarities, the lipid tails for both systems are tilted below the phase transition and become more random above the phase transition temperature. The average area per lipid and bilayer thickness were found less sensitive to phase transition changes as the unsaturated tails are able to buffer reordering of the bilayer structure, as observed from hysteresis loops in annealing simulations. For POPC, changes in the structural properties such as the lipid tail order parameter, hydrocarbon trans-gauche isomerization, lipid tail tilt-angle, and level of interdigitation identified a phase transition at about 270 K. For POPE, three temperature ranges were identified, in which the lower one (270-280 K) was associated with a pre-transition state and the higher (290-300 K) with the post-transition state. In the pre-transition state, there was a significant increase in the number of gauche arrangements formed along the lipid tails. Near the main transition (280-290 K), there was a lowering of the lipid order parameters and a disappearance of the tilted lipid arrangement. In the post-transition state, the carbon atoms along the lipid tails became less hindered as their density profiles showed uniform distributions. This study also demonstrates that atomistic simulations of current lipid force fields are capable of capturing the phase transition behavior of lipid bilayers, providing a rich set of molecular and structural information at and near the main transition state.

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“…Recently, there has been considerable interest in the dehydration effects which accompany the lamellar-to-hexagonal phase transitions in lipid/water systems (Webb et al, 1993;Bryant et al, 1992;Castresana et al, 1992;Bryant & Wolfe, 1989). Biological membranes can incur dehydrationinduced damage correlated to the formation of lateral phase separation and HII phase formation (Crowe & Crowe, 1982;Gordon-Kamm & Steponkus, 1984).…”

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confidence: 97%

Direct evidence for the partial dehydration of phosphatidylethanolamine bilayers on approaching the hexagonal phase

Katsaras

Jeffrey²,

Yang³

et al. 1993

Biochemistry

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X-ray diffraction studies on oriented multilayers of 1-palmitoyl-2-oleoylphosphatidylethanolamine (POPE) in the lamellar gel (L beta) and inverted hexagonal (HII) phases at various temperatures (5-50 degrees C) and relative humidities (0-100%) are reported. One-dimensional electron density profiles of the L beta phase bilayers were constructed to a resolution of better than 4 A using direct methods to solve for the phase problem. In addition, the electron density profiles were fitted favorably using a model in which the atomic groups were assumed to be Gaussian distributed [Wiener, M. C., & White, S. H. (1992) Biophys. J. 61, 434-447]. The X-ray data clearly demonstrate that, at 100% relative humidity (RH), POPE samples exist in two distinct L beta phases, differing primarily in the amount of water between the lamellae. As the hexagonal phase transition temperature is approached, 100% RH POPE samples partially dehydrate, releasing approximately 5 water molecules per phospholipid and experiencing on average a 3-A decrease in repeat spacing. The lower temperature hydrated L beta phase POPE electron density distribution resembles that obtained from the L beta phase 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) bilayers and is unlike the partially dehydrated POPE bilayers.

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Low hydration phase properties of phospholipid mixtures

Cited by 30 publications

References 38 publications

Mechanism of α-Cyclodextrin-lnduced Hemolysis. 1. The Two-Step Extraction of Phosphatidylinositol from the Membrane

Mechanism of α-Cyclodextrin-lnduced Hemolysis. 1. The Two-Step Extraction of Phosphatidylinositol from the Membrane

Molecular Characterization of Gel and Liquid-Crystalline Structures of Fully Hydrated POPC and POPE Bilayers

Direct evidence for the partial dehydration of phosphatidylethanolamine bilayers on approaching the hexagonal phase

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