DMPC-water model

Membrane-Interaction (MI)-QSAR approach developed by Iyer et al. was used to develop predictive models of some organic compounds through BBB, and to simulate the interaction of a solute with the phospholipide-rich regions of cellular membranes surrounded by a layer of water. Molecular dynamics simulations were used to determine the explicit interaction of each test compound with the DMPC-water model (a model of dimyristoylphosphatidylcholine membrane monolayer, constructed using the software Material Studio according to the work done by van der Ploeg and Berendsen). Six MI-QSAR equations were constructed (Eqs. 74-79) ... 

FIGURE 10.7. Total internal reflection fluorescence microscopy of the micro-two-phase system of dode-cane/water. (a) Continuous photons with an average of 11 molecules in the observation area, (b) photon burst with an average of 0.02 molecules in the observation area and (c) extension of the photon burst upon the addition of DMPC. A model for the photon burst upon the observation using single molecule diffusion (d). 

Fig. 7 Comparison of the solid-state 31P-NMR spectra from erythrocyte ghosts (left column) and of DMPC model membranes (right column). Samples are prepared as a non-oriented suspension in excess water (a, d), and as macroscopically oriented membranes on glass slides that are aligned either parallel (b, e) or perpendicular (c, f) to the static magnetic field...

In addition to the long-chain fatty acid molecules described above, a large number of studies have appeared that use IRRAS to study phospholipid monolayers as models of biomembrane interfaces. Mitchell and Dluhy [26] reported the first IRRAS spectra of 1,2-distearoyl-5 -glycero-3-phosphocholine (DSPC), l,2-dimyristoyl-i -glycero-3-phosphocholine (DMPC), and 1,2-di-palmitoyl-,v/ -glycero-3-phosphocholine (DPPC) monolayers at the air-water... 

Values of the equivalent water-alcohol thickness kw, the thickness of the hydrocarbon layers hly the thickness of the polar core h2 and the thickness h (according to three-layer model) of DMPC foam bilayers at different temperatures. 

In 1991, Johnson et al. reported one of the first NR studies of phospholipid bilayers at the solid-solution interface [46]. Although these measurements were not the first to employ NR to study molecules adsorbed at the solid-hquid interface, they did constitute the first measurements of a supported bilayer using NR. A bilayer of dimyristoylphosphatidylcholine (DMPC) was spread on a quartz surface by the fusion and rupturing of smaU unilamellar vesicles. The very smooth, singlecomponent substrate aUowed a complex model of the interface to be constructed from layers corresponding to (i) the quartz, (ii) a thin film of water on the quartz... 

Figure 9.10 Model of 2 x 30 DMPC bilayer in water. On the left is the initial conformation of the starting bilayer with all-frarw lipids note the partly interdigitated bilayer. On the right is the same system after 2 ns at constant volume note the presence of numerous gauche conformers and...

The interaction between bacterial lipopolysaccharides (EPS) and phospholipid cell membranes was studied by various physical methods of deep rough mutant EPS (ReEPS) of Escherichia coH incorporated in phospholipid bilayers as simple models of cell membranes. SS P-NMR spectroscopic analysis suggested that a substantial part of ReEPS is incorporated into l,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers when mixed multilamellar vesicles were prepared. Furthermore the lipid lateral diffusion coefficients measurements at various molar ratios of ReEPS/egg-PC/POPG indicated that the incorporated ReEPS reduces the diffusion coefficients of the phospholipids in the membrane. EUV formed by the ReEPS from Salmonella enterica, eventually in mixture with dilauroyl phosphatidylcholine (DEPC), have been prepared and characterized by DES, SANS and EPR. PFGSE NMR measurements have shown that water permeability through the lipid bilayer is low at room temperature. However, above a transition temperature centered at 30-35 °C, the water permeability increases. ... 

To test a prediction of the mixed bicelle model, PFGSTE H NMR measurements of water diffusion between and across bicellar lamellae were performed in positive and negative magnetically aligned bicelles, composed of DHPC and DMPC, as a function of temperature and of the proportion of added short-chain lipid DHPC. P NMR spectra obtained for each situation confirmed that the DHPC undergoes fast exchange between... 

MD has been appUed for the determination of changes of physical properties of lipid bilayers caused by the incorporated peptide as well as for the determination of possible peptide stractural alterations. MD were performed under periodie boundary conditions using the GROMACS software [68] and the GROMOS87 [69] forcefield with corrections for hpids [70, 71]. The initial models of transmembrane a-helix peptides have been generated by means of HyperChem [72]. Preequilibrated DMPC and DPPC bilayers with 128 lipid molecules and 3655 molecules of water in L hquid-ciystalline state pubhshed by Tieleman et al. [73] have been used in bilayer modehng. For the simulations with membrane in Lp gel state, we created... 

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