Membrane lipids electron spin resonance

Shin Y-K, Ewert U, Budil DE, Ereed JH. Microscopic versus macroscopic diffusion in model membranes by electron spin resonance spectral-spatial imaging. Biophys. J. 1991 59 950-957. Trauble H, Sackmann E. Studies of the crystaUine-hquid crystalline phase transition of lipid model membranes, m. Structure of a steroid-lecitin system below and above the hpid-phase transition. J. Am. Chem. Soc. 1972 94 4499-4510. 

The assumption of membrane softness is supported by a theoretical argument of Nelson et al., who showed that a flexible membrane cannot have crystalline order in thermal equilibrium at nonzero temperature, because thermal fluctuations induce dislocations, which destroy this order on long length scales.188 189 The assumption is also supported by two types of experimental evidence for diacetylenic lipid tubules. First, Treanor and Pace found a distinct fluid character in NMR and electron spin resonance experiments on lipid tubules.190 Second, Brandow et al. found that tubule membranes can flow to seal up cuts from an atomic force microscope tip, suggesting that the membrane has no shear modulus on experimental time scales.191 However, conflicting evidence comes from X-ray and electron diffraction experiments on diacetylenic lipid tubules. These experiments found sharp diffraction peaks, which indicate crystalline order in tubule membranes, at least over the length scales probed by the diffraction techniques.123,192 193... 

Retention of a protein or protein activity after 105,000y, 1 hr Chromatography on gel filtration columns with large pore sizes Electron microscopy—however, sample preparation may partially reconstitute membranes Decrease in solution turbidity, which may be detected by a diminution in light scattering or an enhancement in light transmission Diffusion of membrane lipids as assayed by nuclear magnetic resonance and electron spin resonance... 

Rotational diffusion is characterized by the mean square angular deviation during the time interval At (0 ) = GDrAi. Highly anisotropic motion, which is typical for lipid molecules in the membrane, is usually described by two rotational diffusion coefficients Dr and Dri, which correspond to diffusion about the long diffusion axis and perpendicular to it, respectively. The diffusion coefficients are related to corresponding rotational correlation times measured by nuclear magnetic resonance (NMR), electron spin resonance (ESR), fluorescent depolarization, and so on, as ... 

To understand the function of membrane-active peptides, it is important to know the structure and orientation of the peptide in the membrane. As is evident from Figure 18.1, it is possible to distinguish between, for example, carpet and pore mechanisms of action by determining the peptide s orientation in the membrane. Various techniques, such as electron spin resonance (ESR) [35], infrared (IR) spectroscopy [36-38], circular dichroism (CD) [35, 39,40], and solid-state NMR (SSNMR) [4-7] are used to investigate membrane-active peptides in a quasi-native lipid bilayer environment. In the following sections, methods to determine peptide structure and orientation are presented. 

Information about fluidity and viscosity of bilayers of artificial and natural membranes has been obtained from electron spin resonance studies in which the mobility of the spin-labelled species along the surface plane of the membrane is determined (17). However, the monolayer of either lipid, protein, or lipid-protein systems at the air-water interface, makes an ideal model because several parameters can be measured simultaneously. Surface tension, surface pressure, surface potential, surface viscosity, surface fluorescence and microviscosities, surface radioactivity, and spectroscopy may be determined on the same film. Moreover, the films can be picked up on grids from which they may be observed by electron microscopy, studied further for composition, and analyzed for structure by x-ray diffraction and spectroscopy. This approach can provide a clear understanding of the function and morphology of the lipid and lipid-protein surfaces of experimental membranes. However, the first objective is to obtain molecular correlations of surface tension, pressure, potential, and viscosity. 

Yin JJ, Pasenkiewiczgiemla M, Hyde JS (1987) Lateral diffusion of lipids in membranes by pulse saturation recovery electron-spin-resonance. Proc Natl Acad Sci USA 84 964—968... 

Rehfeld, S.J., Plachy, W.Z., Hou, S.Y., and Elias, PM. (1990). Localization of lipid microdomains and thermal phenomena in murine stratum comeum and isolated membrane complexes an electron spin resonance study, J. Invest. Dermatol, 95 217-223. 

Many electron spin resonance (ESR) studies of different systems have shown that phase separation in lipid layers may lead to a domain-like lateral structure. The area of domain formation can be extended over several hundred A. In this connection the charge-induced domain formation in biomembranes is of special interest for the medicinal chemist. Especially the addition of Ca to negatively charged lipids leads to domain formation. Each lipid component is expected to have a characteristic spontaneous curvature. The Ca - induced domains lead to protrusions in the membrane plane. The lateral variation in the concentration in the plane of the membrane would then lead to a parallel variation in... 

It is known that cholesterol interacts with erythrocyte phospholipids reducing its molecular area (Demel et al., 1967) and, as a consequence, a decrease in the local fluidity of the lipid matrix of the erythrocyte membrane occurs, as it was determined by electron spin resonance studies (Kroes et al., 1972). The results obtained for the inhibition by F of the erythrocyte membrane acetylcholinesterase and (Na" ", KT ")-ATPase from rats fed corn oil and corn oil-plus-cholesterol supplemented diet, respectively, are presented in Table 5. In the case of acetylcholinesterase, the values of n change from 1.5 to 1.0 because of cholesterol dietary effect. Consequently, in the (Na , KT ")-ATPase the values of n vary in an inverse manner (from 2.0 to 3.6). (Bloj et al., 1973 ). 

Montesano, G., Bartucci, R., Belsito, S., Marsh, D., and Sportelli, L. 2001. Lipid membrane expansion and micelle formation by polymer-grafted lipids Scaling with polymer length studied by spin-label electron spin resonance. Biophys. J. 80 1372. 

The nature of lipid-protein interactions in photosynthetic membranes has been examined by means of electron spin resonance (ESR) and saturation transfer ESR (STESR) spectroscopy. Nitroxide-labelled acyl lipids were introduced into thylakoid membranes and sub-membrane preparations and the resultant ESR spectra were analysed under various conditions. 

Devaux, P.F., Davoust, J., and Rousselet, A., 1981, Electron spin resonance studies of lipid-protein interactions in membranes. Biochemical Symposia, 46 207. 

The hydrocarbon chains of the lipid bilayer are in a liquid-like state as evidenced by X-ray diffraction, electron spin resonance spectroscopy, and differential scanning calorimetry studies. A quantitative characterization of the hydrocarbon chain order in lipid bilayers by means of H-NMR became possible by selectively deuterating both fatty acyl chains in a lipid molecule. Measurement of the deuterium quadrupole splittings, Avq, allowed calculation of the order parameter of the C—D bond vector at each labeled carbon atom. The variation of the order parameter ScdI with the position of the labeled carbon atom in the membrane is the so-called order profile. An... 

A variety of physical techniques such as NMR, electron spin resonance (ESR), X-ray diffraction, fluorescence spectroscopy, and differential thermal analysis have been applied to the study of natural and synthetic membranes. The usefulness of these methods has been discussed in several reviews (Chapman, 1968 Luzzati, 1968 Luzzati et al., 1969 Chapman and Dodd, 1971 Gaffney, 1974 Azzi, 1974 Lee et al., 1974a) which indicate that considerable progress has been made in understanding the structure and properties of membranes. Nevertheless, the manner in which the lipid and protein portions of membranes interact is unresolved. For this reason it is not possible to discuss in detail the mechanisms which control the function of membrane-bound enzymes. This chapter, therefore, presents evidence useful in establish-... 

To remove intrinsic proteins from a membrane it is necessary to solubilize the molecules using detergents which can break the hydrophobic interactions with lipids. The lipids adjacent to the proteins experience a different environment from the bulk lipid of the membrane and this has led to the concept of boundary lipids. ESR (electron spin-resonance) studies showed that lipids residing at the lipid-protein interface exhibited increased order parameters (restricted motion) in the acyl chain region. Recent experiments, however, paint a different picture. First, the lipid-protein... 

Buettner GR, Kelley EE, Burns CP. Membrane lipid free radicals produced from L1210 murine leukemia cells by photofrin photosensitization an electron paramagnetic resonance spin trapping study. Cancer Res 1993 53 3670-3. 

Therefore, a purpose of the present work was to study the effect of DPhO and BM-DPhO in a wide range of concentration (10 -10 mol/1) on the endoplasmic reticulum membranes (microsomes) isolated from Balb-line mice. Electron paramagnetic resonance (EPR) technique and spin-probe method were used to study the dynamic structure of deep hydrophobic and surface lipid regions of microsomal membranes. We suggested the different effects of DPhO and IM-DPhO on the membrane lipids structure, because iod-methylate derivative is charged. 

During recent years much information has been obtained about the structure of biological membranes. This information has come in part from biochemical studies (the isolation of different chemical compounds from the cell membranes), x-ray diffraction, electron-spin and nuclear-spin magnetic resonance, spectroscopy, and especially the use of the electron microscope. Cell membranes, such as the membrane of the red blood cell, consist of about equal amounts of lipids and proteins. There is... 

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