Nuclear magnetic resonance studies of amphiphile hydration

Taylor, Ronald P.; Huang, Chunbo; Broccoli, Anthony V.; Leake, L.R.

doi:10.1016/0003-9861(77)90421-0

Cited by 14 publications

(2 citation statements)

References 17 publications

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“…Cholesterol might also be expected to modify the repulsive pressures between adjacent bilayers for several reasons. First, in terms of the hydration pressure, it is known that cholesterol modifies the hydration of bilayers (Taylor et al, 1977;Jendrasiak & Hasty, 1974; Ter-Minassian-Saraga & Madelmont, 1982), the depth of water penetration into bilayers (Simon et al, 1982), and the association of adjacent PC1 bilayers (Stamatatos & Silvius, 1987). Cholesterol has also been shown to be a major factor in the formation of atherosclerotic plaques (Small & Shipley, 1974).…”

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Cholesterol modifies the short-range repulsive interactions between phosphatidylcholine membranes

McIntosh¹,

Magid²,

Simon³

1989

Biochemistry

171

198

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Pressure versus distance relationships have been obtained for egg phosphatidylcholine bilayers containing a range of cholesterol concentrations. Water was removed from between adjacent bilayers by the application of osmotic pressures in the range of 0.4-2600 atm (4 x 10(5)-2.6 x 10(9) dyn/cm2), and the distance between adjacent bilayers was obtained by Fourier analysis of X-ray diffraction data. For applied pressures up to about 50 atm and bilayer surface separations of 15-5 A, the incorporation of up to equimolar cholesterol has little influence on plots of pressure versus bilayer separation. However, for the higher applied pressures, cholesterol reduces the interbilayer separation distance by an amount that depends on the cholesterol concentration in the bilayer. For example, the incorporation of equimolar cholesterol reduces the distance between bilayers by as much as 6 A at an applied pressure of 2600 atm. At this applied pressure, electron density profiles show that the high-density head-group peaks from apposing bilayers have merged. This indicates that equimolar concentrations of cholesterol spread the lipid molecules apart in the plane of the bilayer enough to allow the phosphatidylcholine head groups from apposing bilayers to interpenetrate as the bilayers are squeezed together. All of these X-ray and pressure-distance data indicate that, by reducing the volume fraction of phospholipid head groups, cholesterol markedly reduces the steric repulsion between apposing bilayers but has a much smaller effect on the sum of the longer ranged repulsive hydration and fluctuation pressures. Increasing concentrations of cholesterol monotonically increase the dipole potential of egg phosphatidylcholine monolayers, from 415 mV with no cholesterol to 493 mV with equimolar cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

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mentioning

confidence: 99%

Cholesterol modifies the short-range repulsive interactions between phosphatidylcholine membranes

McIntosh¹,

Magid²,

Simon³

1989

Biochemistry

171

198

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“…A distinct 4.lS-l band due to ordered gel-state phospholipid, observed alone at 0% cholesterol, becomes accompanied by a broad 4.7-l band at 20%, As cholesterol composition increases, the diffracted energy in the 4.7 -l band increases while the 4 . lS-A line decreases, with complete disappearance of the 4.15-l band at 33 mole percent cholesterol (Engelman and Rothman, 1972 (Taylor et al , 1977 proposed to differ between the two liquid phases of the DMPC/cholesterol and DPPC/cholesterol phase diagrams (Sankaram and Thompson, 1991). In the L(I phase, cholesterol localizes toward the bilayer median so that it partially spans the hydrophobic region of each monolayer, whereas in the Lo phase it aligns with phospholipids in either monolayer.…”

Section: F Models Of Cholesterol/phospholipid Interactionsmentioning

confidence: 99%

The Effect of Cholesterol on the Binding and Insertion of Cytochrome b5 into Liposomes of Phosphatidylcholines

Taylor¹

1993

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Surface viscosities of phospholipids alone and with cholesterol in monolayers at the air‐water interface

Evans¹,

Williams²,

Tinoco³

1980

Lipids

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Surface viscosities in lipid monolayers at the air-water interface were measured by the oscillating pendulum method. The logarithms of successive oscillations decreased linearly with time. Surface viscosity is reported here in terms of the rate constant, k, for decay of oscillation. Viscosities were measured as a function of surface pressure at 22 +-2 C. Lipids investigated included cholesterol, 1-palmitoyl-2-arachidonoyl phosphatidylcboline (PC), 4 other unsaturated PC, 1-palmitoyl-2-stearoyl PC, 1,2-distearoyl PC, 1-palmitoyl-lysophosphatidylcholine, l-palmitoyl-lysophosphatidylserine, tetrapalmitoyl bisphosphatidic acid, and the dipalmitoyl species of PC, phosphatidylethanolamine (PE), phosphatidyldimethylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidic acid. Pressure-area curves are presented for the saturated phospholipids. Surface viscosities of most of the phospholipids were high and increased with increasing surface pressure. However, surface viscosities in monolayers of cholesterol, 1-pahhitoyl-2-arachidonoyl PC, lysophosphatidylcholine or lysophosphatidylserine were very low and barely detectable under our experimental conditions. One mol % of cholesterol in monolayers of dipalmitoyl PC greatly reduced the surface viscosity of the film and, in mixed films containing 10% or more of cholesterol, surface viscosity was too low to measure. Cholesterol also reduced surface viscosities in monolayers of the other dipalmitoyl phospholipids. It is suggested that cholesterol functions in lung surfactant by reducing the surface viscosity of its highly saturated phospholipid components.

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Nuclear magnetic resonance studies of amphiphile hydration

Cited by 14 publications

References 17 publications

Cholesterol modifies the short-range repulsive interactions between phosphatidylcholine membranes

Cholesterol modifies the short-range repulsive interactions between phosphatidylcholine membranes

The Effect of Cholesterol on the Binding and Insertion of Cytochrome b5 into Liposomes of Phosphatidylcholines

Surface viscosities of phospholipids alone and with cholesterol in monolayers at the air‐water interface

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