DMPC bilayers

Figure 13.9 (a) Temperature dependence of p on the DMPC bilayer on glass (white) and silicon (black), (b) Dependence ofp on the molar fraction of a cationic DMTAP additive in the DMPC bilayer. Adapted from Ref [48] with permission. 

FIGURE 10.8 Profiles of the relative oxygen diffusion-concentration product across the DMPC bilayer containing 0 (O) and 10mol% zeaxanthin ( ) at 25°C. The approximate locations of nitroxide moieties of spin labels are indicated by arrows. The value of the oxygen diffusion-concentration product in water can be obtained from the oxygen diffusion coefficient and oxygen concentration in water equilibrated with air at 25°C. (From Subczynski, W.K. et al., Biochim. Biophys. Acta, 1068, 68, 1991. With permission.)... 

Figure 35 13C CPMAS NMR spectra of [l- 3C]Val- and [3- 3C]Ala-labelled bR reconstituted in DMPC bilayer (1 50 mole ratio) at various temperatures from 40 (A) to —10 °C (D). The methylene peak-position of the fatty acyl chain of the lipid at 32 and 30 ppm is a good indicator of the gel and liquid-crystalline phase, respectively. From Ref. 206 with...

Fig. 8 Representative solid-state 19F-NMR spectra of 19F-labelled gramicidin S (substituted at both Leu positions with 4F-Phg), embedded in macroscopically oriented ghost membranes (left column) and DMPC bilayers (right column) at a peptide-to-lipid ratio of about 1 40 [in (F) the lipid was 1 1 DMPC/cholesterol]. Depending on temperature, the peptide can assume different alignment states, which are strikingly similar in the native membranes and the model bilayers...

Strandberg E, Wadhwani P, Tremouilhac P, Durr UHN, Ulrich AS (2006) Solid-state NMR analysis of the PGLa peptide orientation in DMPC bilayers structural fidelity of H-2-labels versus high sensitivity of F-19-NMR. Biophys J 90 1676-1686... 

The overall density profiles across the DMPC bilayer are given in Figure 13 (see also refs. [84-86,92,95,98]). Together with these profiles, the water-density... 

Figure 13. The overall density (volume fraction) profile for DMPC bilayers is shown here. Apart from the distribution of the overall DMPC molecules, the density distribution of the head-group units (including the choline group, the phosphate group and the oxygens of the glycerol unit), and the end groups of the lipid tails are also indicated. In addition, the free-volume profile and the water profile are depicted...

Figure 15. The electrostatic potential (V) profile (dashed line left ordinate) and the overall charge (in units of elementary charges) profile (continuous line right ordinate) across the DMPC bilayer, as found by SCF calculations...

Figure 16. The distribution of the ions across the DMPC bilayer...

Figure 17. Order parameter profile for the two tails of DMPC bilayers. The chain closest to the head group is named sn and the other one sn2. Segments closest to the glycerol backbone are numbered t = 1, and the chain ends are t = 16. The lines are drawn to guide the eye...

Fig. 2 Solid state F-NMR spectra of GS-3/3 in oriented DMPC bilayers, measured at 25 °C according to published procedures [17-19,22]. Samples are prepared with a peptidedipid molar ratio of 1 80 (A), 1 40 (B), and 1 20 (C). The arrows indicate the signals emerging at high peptide concentration, corresponding to a new re-aligned state of the peptide. The dashed line shows respective powder pattern of the lyophUized peptide...

Using preformed pores in a DMPC bilayer, Gurtovenko and Vattulainen [82] investigated the translocation of DMPC across a pore. It was shown that multiple lipids diffused across the pore before it dissipated, providing support for pore-mediated flip-flop as mechanism for passive flip-flop. The timescale for pore dissipation was found to be 35-200 ns, at the limits of current computational capability for equilibrium simulations. 

Fig. 3.45 Effect of drug concentration on the partition coefficients of tamoxifen (open symbols) and 4-hydroxytamoxifen (closed symbols) in DMPC bilayers (A) and in liposomes of sarcoplasmic reticulum lipids and native membranes (B). Note that the linear correlation between Kp and drug concentration is...

Fig. 3.49 DSC thermogram of hydrated DMPC bilayers containing losartan at different mole fractions, x, indicated. (Reprinted from Fig. 2 of ref. 157 with permission from Elsevier Science.)...

The values of Q obtained from the best fit of Eq. (3.115) (the solid lines in Fig. 3.95) to the experimental data (the circles in Fig. 3.95) assuming Cc = Ce are (1.93 0.04)-10 9 J for temperatures lower than 23°C and (8.03 0.19)-10 2° J for temperatures higher than 23°C. The possible error arising from the assumption that Cc = Ce is analysed elsewhere [384] it can raise the Q value by up to 20%. The good fit of the experimental results to the theoretical dependence and the high stability of the foam bilayers with respect to their rupture even under a-particle irradiation, show that in the case of DMPC bilayers the assumption Cc = Ce is probably accurate. 

Lyubartsev has also developed a multiscale parameterisation method that has been used to systematically build a CG model of a DMPC bilayer. Lyubartsev uses an inverse Monte Carlo method to generate the CG parameters from an underlying atomistic simulation. The atomistic simulation trajectory is analysed to generate the radial distribution functions (RDFs) for the CG bead model. These RDFs can be converted into pairwise interaction potentials between the beads. The... 

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