Acyl Chain Orientational Order
نویسنده
چکیده
The deuterium nuclear magnetic resonance (2H NMR) spectrum of perdeuterated tetradecanol in a mixture of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) and water was used to compare the variation of the acyl chain orientational order parameter, S(n), with carbon position, n, in the liquid crystalline lamellar (La) and hexagonal (HI,) phases. The characteristic independence of S(n) with n (plateau) normally observed in the La phase is replaced by a more rapid decrease of S(n) with n in the HI, phase. It is suggested that as a consequence of the geometrical characteristics of the HI, phase, there is an increase in conformational freedom available to different parts of the acyl chain.
منابع مشابه
Order parameters and areas in fluid-phase oriented lipid membranes using wide angle X-ray scattering.
We used wide angle x-ray scattering (WAXS) from stacks of oriented lipid bilayers to measure chain orientational order parameters and lipid areas in model membranes consisting of mixtures of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/cholesterol and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol in fluid phases. The addition of 40% cholesterol to either DOPC or DPPC changes...
متن کاملInfluence of highly polyunsaturated lipid acyl chains of biomembranes on the NMR order parameters.
We investigate the effect of specific conformations of double-bond segments in highly polyunsaturated acyl chains on the deuterium (2)H NMR order parameters of a fully hydrated 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine (SDPC, 18:0/22:6 PC) lipid bilayer. The system is analyzed by performing a molecular dynamics simulation study at ambient conditions in the fluid lamellar phase. B...
متن کاملPressure-induced ordering in mixed-lipid bilayers.
Isothermal application of hydrostatic pressure to liquid crystalline phospholipid bilayers increases chain segment orientational order and thus chain extension. By using pressure to perturb chain order in single-component bilayers and bilayers comprising a binary mixture of lipids, it is possible to compare the relative influences of intrinsic lipid properties and collective bilayer properties ...
متن کاملThermodynamics of phosphatidylcholine-cholesterol mixed model membranes in the liquid crystalline state studied by the orientational order parameter.
It is shown that good estimates of the activity of cholesterol in phosphatidylcholine-cholesterol mixed model membranes are obtained by examining the orientational order parameter S of cholestane spin probe (CSL) that is obtained from electron spin resonance by spectral simulation. By introducing thermodynamic stability conditions of liquid mixtures, the variation of activity (or S) as a functi...
متن کاملAn electron spin resonance study of interactions between phosphatidylcholine and phosphatidylserine in oriented membranes.
A detailed electron spin resonance (ESR) study of mixtures of 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and phosphatidylserine (POPS) in oriented multilayers in the liquid crystalline phase is reported with the purpose of characterizing the effects of headgroup mixing on the structural and dynamical properties of the acyl chains. These studies were performed over a range of blends of POPC...
متن کامل