Thermotropism and hydration properties of POPE and POPE-cholesterol systems as revealed by solid state2H and31P-NMR

Marinov, R; Dufourc, Érick J.

doi:10.1007/bf00576714

Cited by 22 publications

(18 citation statements)

References 31 publications

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“…Similarly, for POPE/Chol 0.2 the Ld-to-H II phase transition is detected transition of around 55 ı C (Paré and Lafleur 1998). The amplitude rise also agrees with the expected increase of n W from the Ld phase to the H II phase (Rand and Fuller 1994;Marinov and Dufourc 1996). However, the change is much larger than expected from this increase.…”

Section: Influence Of Lipid Phasesupporting

confidence: 83%

“…6.6a) is larger than expected from structural or NMR data that yield n W of around 15 (Marinov and Dufourc 1996;Rappolt et al 2003). Thus, also our POPE multibilayers contain defects and are irregular to some extent.…”

Section: Influence Of Lipid Compositionmentioning

confidence: 59%

“…6.6b). The value of n W in this case is below the fully hydrated level but above the level where only the interfacial water is present, which is around n W D 12 for DMPC (Pasenkiewicz-Gierula et al 1997) and around n W D 8 for POPE (Marinov and Dufourc 1996), respectively. As we saw above in the experiment with osmotic pressure, we can expect that the dehydration reduces the number of defects in the lamellar structure.…”

Section: Influence Of Lipid Compositionmentioning

confidence: 74%

“…There were different attempts to quantify the number of water molecules in these different classes for example by NMR (Marinov and Dufourc 1996;Faure et al 1997), X-ray structural studies (Nagle and TristramNagle 2000) and calorimetry (Kodama et al 2001). Useful information about the amount and properties of particular water molecules can be obtained also from molecular dynamics (MD) simulations (Pasenkiewicz-Gierula et al 1997;Pinnick et al 2010).…”

Section: Irementioning

confidence: 99%

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Long-Range Lipid-Water Interaction as Observed by ATR-FTIR Spectroscopy

Arsov

2015

Subcellular Biochemistry

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It is commonly assumed that the structure of water at a lipid-water interface is influenced mostly in the first hydration layer. However, recent results from different experimental methods show that perturbation extends through several hydration layers. Due to its low light penetration depth, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is specifically suited to study interlamellar water structure in multibilayers. Results obtained by this technique confirm the long-range water structure disturbance. Consequently, in confined membrane environments nearly all water molecules can be perturbed. It is important to note that the behavior of confined water molecules differs significantly in samples prepared in excess water and in partially hydrated samples. We show in what manner the interlamellar water perturbation is influenced by the hydration level and how it is sequentially modified with a step-by-step dehydration of samples either by water evaporation or by osmotic pressure. Our results also indicate that besides different levels of hydration the lipid-water interaction is modulated by different lipid headgroups and different lipid phases as well. Therefore, modification of interlamellar water properties may clarify the role of water-mediated effects in biological processes.

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Section: Influence Of Lipid Phasesupporting

confidence: 83%

Section: Influence Of Lipid Compositionmentioning

confidence: 59%

Section: Influence Of Lipid Compositionmentioning

confidence: 74%

Section: Irementioning

confidence: 99%

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Long-Range Lipid-Water Interaction as Observed by ATR-FTIR Spectroscopy

Arsov

2015

Subcellular Biochemistry

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“…4 C-E), indicating low hydration. 2 H NMR spectra of D 2 O bound to POPE membranes without and with the TMD at similar water contents (34,35) show a superposition of a quadrupolar splitting, which results from tightly bound water, and an isotropic peak, which results from free water (SI Appendix, Fig. S7C).…”

Section: Piv5 Tmd Changes Its Conformation In Response To the Membranementioning

confidence: 99%

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

Yao

Lee

Waring

et al. 2015

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

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The C-terminal transmembrane domain (TMD) of viral fusion proteins such as HIV gp41 and influenza hemagglutinin (HA) is traditionally viewed as a passive α-helical anchor of the protein to the virus envelope during its merger with the cell membrane. The conformation, dynamics, and lipid interaction of these fusion protein TMDs have so far eluded high-resolution structure characterization because of their highly hydrophobic nature. Using magicangle-spinning solid-state NMR spectroscopy, we show that the TMD of the parainfluenza virus 5 (PIV5) fusion protein adopts lipid-dependent conformations and interactions with the membrane and water. In phosphatidylcholine (PC) and phosphatidylglycerol (PG) membranes, the TMD is predominantly α-helical, but in phosphatidylethanolamine (PE) membranes, the TMD changes significantly to the β-strand conformation. Measured order parameters indicate that the strand segments are immobilized and thus oligomerized. 31 P NMR spectra and small-angle X-ray scattering (SAXS) data show that this β-strand-rich conformation converts the PE membrane to a bicontinuous cubic phase, which is rich in negative Gaussian curvature that is characteristic of hemifusion intermediates and fusion pores. 1 H-31 P 2D correlation spectra and 2 H spectra show that the PE membrane with or without the TMD is much less hydrated than PC and PG membranes, suggesting that the TMD works with the natural dehydration tendency of PE to facilitate membrane merger. These results suggest a new viral-fusion model in which the TMD actively promotes membrane topological changes during fusion using the β-strand as the fusogenic conformation.solid-state NMR spectroscopy | small-angle X-ray scattering | conformational polymorphism | membrane curvature | peptide-membrane interactions V iral fusion proteins mediate entry of enveloped viruses into cells by merging the viral lipid envelope and the cell membrane. The membrane-interacting subunit of these glycoproteins contains two hydrophobic domains: a fusion peptide (FP) that is usually located at the N terminus and a transmembrane domain (TMD) at the C terminus (1). Together, these domains sandwich a water-soluble ectodomain with a helical segment that trimerizes into a coiled coil. During virus-cell fusion, the trimeric protein, which initially adopts a compact structure, unfolds to an extended intermediate that exposes the FP to the target cell membrane while keeping the TMD in the virus envelope. This extended conformation then folds onto itself to form a trimer of hairpins, in so doing pulling the cell membrane and the virus envelope into close proximity (2, 3). Subsequently, the FP and TMD are hypothesized to deform the two membranes and dehydrate them (4), eventually causing a fusion pore and a fully merged membrane. In the postfusion state, most viral fusion proteins exhibit a six-helixbundle structure in the ectodomain due to the trimer of hairpins (5).This model of virus-cell fusion largely derives from crystal structures of fusion proteins in the pre-and postfusion st...

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NMR : Lipids

Dufourc¹

2008

Wiley Encyclopedia of Chemical Biology

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Lipid structure and dynamics are keys factors for cell life. Phospholipids are essential in signalling pathways as they are recognition sites at the membrane surface. Other lipids such as cholesterol and sphingomyelin are crucial molecules in maintaining membrane integrity and are involved in membrane domains (rafts). NMR both with its liquid and solid‐state facets is a very powerful tool for deciphering both the structure and the dynamics of various classes of lipids. Lipids extracted from membranes and dissolved in organic solvents can reveal their molecular structure when observed with multinuclear one‐dimensional or two‐dimensional solution NMR. Multinuclear, wide‐line, solid‐state NMR brings information on the nature of the membrane phase (lamellar, hexagonal, isotropic, etc.), its dynamics (diffusion, fluid/gel, or liquid‐ordered with cholesterol) and the molecular structure of embedded lipids when using the Magic Angle Spinning technique.

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Thermotropism and hydration properties of POPE and POPE-cholesterol systems as revealed by solid state2H and31P-NMR

Cited by 22 publications

References 31 publications

Long-Range Lipid-Water Interaction as Observed by ATR-FTIR Spectroscopy

Long-Range Lipid-Water Interaction as Observed by ATR-FTIR Spectroscopy

Viral fusion protein transmembrane domain adopts β-strand structure to facilitate membrane topological changes for virus–cell fusion

NMR : Lipids

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