Area/lipid of bilayers from NMR

Nagle, John F.

doi:10.1016/s0006-3495(93)81514-5

Cited by 318 publications

(276 citation statements)

References 18 publications

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“…Recently, the gravimetric method has been further modified by combining it with NMR S CD order parameter data as a function of osmotic pressure (Koenig et al, 1997). There is uncertainty in converting S CD data into absolute values of A (Nagle, 1993;Koenig et al, 1997), but Koenig et al (1997) argue that changes in A are accurately obtained. By using the gravimetric method to obtain A at low hydration, where it is likely that most of the water does go between the bilayers, and by using the K A obtained from NMR, Koenig et al (1997) obtained at T = 30°C.…”

Section: Our Resultsmentioning

confidence: 99%

“…Because there are so many different thicknesses that can be defined, hydrocarbon thickness D C , Luzzati thickness D B and steric thickness we prefer to focus upon the average area A per lipid at the liquid interface, from which the various thicknesses can then be obtained (Nagle and Wiener, 1988). For example, for DPPC, one of the most studied lipids, literature uncertainties in range from 56 to 73 Å 2 (Nagle, 1993). This range is enormous, especially when one considers that the DPPC gel G (i.e. )…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fluid phase structure of EPC and DMPC bilayers

Petrache

Tristram-Nagle

Nagle

1998

Chemistry and Physics of Lipids

243

236

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X-ray diffraction data taken at high instrumental resolution were obtained for EPC and DMPC under various osmotic pressures, primarily at T = 30°C. The headgroup thickness D HH was obtained from relative electron density profiles. By using volumetric results and by comparing to gel phase DPPC we obtain areas and . The analysis also gives estimates for the areal compressibility K A . The A F results lead to other structural results regarding membrane thickness and associated waters. Using the recently determined absolute electrons density profile of DPPC, the A F results also lead to absolute electron density profiles and absolute continuous transforms |F(q)| for EPC and DMPC. Limited measurements of temperature dependence show directly that fluctuations increase with increasing temperature and that a small decrease in bending modulus K c accounts for the increased water spacing reported by Simon et al. (1995) Biophys. J. 69, 1473−1483.

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Section: Our Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fluid phase structure of EPC and DMPC bilayers

Petrache

Tristram-Nagle

Nagle

1998

Chemistry and Physics of Lipids

243

236

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“…The area per lipid projected on the bilayer plane, A L , can be experimentally estimated from X-ray or neutron scattering experiments [281], or, indirectly, from the lipid order parameter profiles [283]. In simulated bilayers, the area per lipid is usually calculated by dividing the total bilayer projected area by half the number of lipids in the bilayer, since, on average, there is an equal number of lipids in each leaflet.…”

Section: A2 Structural Properties Of Lipid Bilayersmentioning

confidence: 99%

Mesoscopic models of biological membranes

Venturoli¹,

et al. 2006

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Phospholipids are the main components of biological membranes and dissolved in water these molecules self-assemble into closed structures, of which bilayers are the most relevant from a biological point of view. Lipid bilayers are often used, both in experimental and by theoretical investigations, as model systems to understand the fundamental properties of biomembranes. The properties of lipid bilayers can be studied at different time and length scales. For some properties it is sufficient to envision a membrane as an elastic sheet, while for others it is important to take into account the details of the individual atoms. In this review, we focus on an intermediate level, where groups of atoms are lumped into pseudo-particles to arrive at a coarse-grained, or mesoscopic, description of a bilayer, which is subsequently studied using molecular simulation.The aim of this review is to compare various strategies to coarse grain a biological membrane. The conclusion of this comparison is that there can be many valid different strategies, but that the results obtained by the various mesoscopic models are surprisingly consistent. A second objective of this review is to illustrate how mesoscopic models can be used to obtain a better understanding of experimental systems. The advantage of coarse-grained models is that these can be simulated very efficiently, so that phenomena involving large systems, or requiring a large number of simulations, can be studied in detail. This is illustrated with the study of the relation between the phase behavior of a membrane and the structure of the phospholipids, and the membrane structural changes due to molecules (such as alcohols, cholesterol and anesthetics) adsorbed to the membrane. We then discuss the effect of transmembrane peptides on the local structure of a membrane and the mechanism of vesicle fusion and fission.

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“…The hydrophobic thickness of POPC bilayers, L, is conveniently estimated from average hydrocarbon chain order parameters of the saturated palmitic acid chain (Bloom and Mouritsen 1988;Nagle 1993) by the equation (8) where n is the number of carbon atoms per palmitic acid chain, and S av the average chain order parameter. We determined S av =0.181 by 2 H NMR on oriented POPC bilayers at conditions identical to those in the neutron diffraction experiments (Kimura & Gawrisch, unpublished).…”

Section: Water Distribution From Neutron Diffractionmentioning

confidence: 99%

Hydration of POPC bilayers studied by 1H-PFG-MAS-NOESY and neutron diffraction

et al. 2007

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The stability of lipid bilayers is ultimately linked to the hydrophobic effect and the properties of water of hydration. Magic angle spinning (MAS) nuclear Overhauser enhancement spectroscopy (NOESY) with application of pulsed magnetic field gradients (PFG) was used to study the interaction of water with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers in the fluid phase. NOESY cross-relaxation between water and polar groups of lipids, but also with methylene resonances of hydrophobic hydrocarbon chains, has been observed previously. This observation led to speculations that substantial amounts of water may reside in the hydrophobic core of bilayers. Here, the results of a quantitative analysis of cross-relaxation in a POPC/water mixture are reported. Coherences were selected via application of pulsed magnetic field gradients. This technique shortens acquisition times of NOESY spectra to 20 minutes and reduces t 1 -spectral noise, enabling detection of weak crosspeaks, like those between water and lipids, with higher precision than with non-gradient NOESY methods. The analysis showed that water molecules interact almost exclusively with sites of the lipid-water interface, including choline-, phosphate-, glycerol-, and carbonyl groups. The lifetime of lipid-water associations is rather short, on the order of 100 ps, at least one order of magnitude shorter than the lifetime of lipid-lipid associations. The distribution of water molecules over the lipid bilayer was measured at identical water content by neutron diffraction. Water molecules penetrate deep into the interfacial region of bilayers but water concentration in the hydrophobic core is below the detection limit of one water molecule per lipid, in excellent agreement with the cross-relaxation data.

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Area/lipid of bilayers from NMR

Cited by 318 publications

References 18 publications

Fluid phase structure of EPC and DMPC bilayers

Fluid phase structure of EPC and DMPC bilayers

Mesoscopic models of biological membranes

Hydration of POPC bilayers studied by 1H-PFG-MAS-NOESY and neutron diffraction

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