A Spin Label Study of the Influence of Cholesterol on Phospholipid Multibilayer Structures

1971 ◽  
Vol 49 (5) ◽  
pp. 614-622 ◽  
Author(s):  
Jen-Chang Hsia ◽  
Henry Schneider ◽  
Ian C. P. Smith
Keyword(s):  
Simple Model ◽  
Angular Dependence ◽  
Spin Label ◽  
Rotational Frequency ◽  
Label Study ◽  
Egg Lecithin ◽  
Dipalmitoyl Lecithin ◽  
Hyperfine Splittings ◽  
Degree Of Order ◽  
Limiting Value

Cholesterol increases the degree of order indicated by the spin-labelled derivative of cholestane (3-spiro-(2′-(N-oxyl-4′,4′-dimethyloxazoIidine))-cholestane) in a hydrated multibilayer structure of egg lecithin. Estimates of the angle between the long axis of the label and the lamellar plane were obtained using a simple model for the effect of this angle on the angular dependence of the hyperfine splittings of the spin label. The deviation from perpendicularity was ~28 + 5° in the absence of cholesterol. This deviation decreased to a limiting value of ~10 ± 3° at 25 mole% cholesterol. The limiting deviation was smaller when dipalmitoyl lecithin was substituted for egg lecithin, indicating the importance of the nature of the acyl residues in this effect.The rotational frequency of the spin label about its long axis depended upon whether or not the multibilayer structure had been in contact with an aqueous phase. Before wetting, this frequency was « 75 × 106 s−1; after wetting it was » 75 × 106 s−1.

Intermolecular Steric Interactions and Lipid Chain Fluidity in Phospholipid Multibilayers. A Spin Label Study

1974 ◽  
Vol 52 (7) ◽  
pp. 631-636 ◽  
Author(s):  
D. Marsh
Keyword(s):  
Stearic Acid ◽  
Spin Label ◽  
Spin Labels ◽  
Energy Separation ◽  
Effective Energy ◽  
Label Study ◽  
Steric Interactions ◽  
Egg Lecithin ◽  
Lipid Chain ◽  
Ordered State

The temperature variation of the spectra of stearic acid spin labels has been investigated in oriented egg lecithin multibilayers. The temperature behavior is characterized by an effective value for the energy separation between trans and gauche conformations in the lipid chains. Comparison with bilayers containing cholesterol indicates that this effective energy is sensitive to intermolecular steric interactions. The large value for the effective gauche energy suggests that part of the lipid chains are in a relatively ordered state even in unsaturated lecithin systems.

A spin label study of the effects of sterols on egg lecithin bilayers

1979 ◽  
Vol 23 (3) ◽  
pp. 201-211 ◽  
Author(s):  
Richard Semer ◽  
Edward Gelerinter
Keyword(s):  
Spin Label ◽  
Label Study ◽  
Egg Lecithin

scholarly journals A spin label study of the thyroid hormone-binding sites in human plasma thyroxine transport proteins.

1981 ◽  
Vol 256 (2) ◽  
pp. 831-836
Author(s):  
S.Y. Cheng ◽  
G. Rakhit ◽  
F. Erard ◽  
J. Robbins ◽  
C.F. Chignell
Keyword(s):  
Thyroid Hormone ◽  
Human Plasma ◽  
Spin Label ◽  
Binding Sites ◽  
Transport Proteins ◽  
Hormone Binding ◽  
Label Study

scholarly journals Spin-label study of hemoglobin conformations in solution.

1967 ◽  
Vol 58 (1) ◽  
pp. 19-26 ◽  
Author(s):  
S. Ogawa ◽  
H. M. McConnell
Keyword(s):  
Spin Label ◽  
Label Study

The Orientation of Cytochrome c Oxidase in Coupled Phospholipid Membrane Vesicles—A Spin-Label Study

1975 ◽  
Vol 53 (3) ◽  
pp. 364-370 ◽  
Author(s):  
J. A. Kornblatt ◽  
W. L. Chen ◽  
J. C. Hsia ◽  
G. R. Williams
Keyword(s):  
Molecular Weight ◽  
Binding Site ◽  
Cytochrome Oxidase ◽  
Spin Label ◽  
Resonance Spectrum ◽  
Membrane Vesicles ◽  
Phospholipid Membrane ◽  
Vesicle Membrane ◽  
Exterior Surface ◽  
Label Study

Cytochrome oxidase, an enzyme containing six different subunits, has been shown to span the inner mitochrondrial membrane. The arrangement of the subunits within the membrane is unknown. We have specifically labeled the 25 000 molecular weight subunit with a spin-label derivative of N-ethylmaleimide, 3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (NEM-SL(5)). NEM-SL(5)-labeled cytochrome oxidase can be incorporated into phospholipid membranes to form coupled vesicles of the Hinkle, Kim &Racker ((1972) J. Biol. Chem. 247, 1338–1339) type. The resonance spectrum of NEM-SL(5) is similar in both soluble and vesicular cytochrome oxidase. Since ascorbate has been shown to reduce only spin label that is exposed to the exterior surface of a closed vesicle, we have used ascorbate to determine the NEM-SL(5)-binding site in the coupled vesicles. NEM-SL(5)-labeled cytochrome oxidase vesicles are reduced by 10 mM ascorbate with [Formula: see text] of 1 min at 22 °C. The rate of reduction is relatively independent of temperature. We conclude that (1) cytochrome oxidase is unidirectionally or preferentially oriented in the vesicle membrane, and (2) the NEM-SL(5)-binding site on the 25 000 molecular weight subunit is exposed to the external aqueous medium.

Degrees of order of solubilized alkanes, alcohols, carboxylates, and carboxylic acids in oriented lyomesophases

1977 ◽  
Vol 55 (12) ◽  
pp. 2404-2410 ◽  
Author(s):  
Douglas M. Chen ◽  
Fred Y. Fujiwara ◽  
Leonard W. Reeves
Keyword(s):  
Carboxylic Acids ◽  
Chain Length ◽  
Linear Increase ◽  
Short Chain ◽  
Appreciable Amount ◽  
Linear Region ◽  
Short Chain Length ◽  
Chain Lengths ◽  
Degree Of Order ◽  
Limiting Value

The degree of order of solubilized molecules and ions in oriented lyomesophases has been determined at specifically deuterated C—D bond axes from the quadrupole splitting of the deuterium magnetic resonance. Mixtures at low concentration of specifically deuterated alkanes, alcohols, carboxylic acids, and carboxylates of different chain length have been observed in host cationic and anionic lyomesophases. The degree of order of a given C—D position in alcohols increases strongly with chain length up to a length comparable with the host detergent. A broad series of carboxylic acids and carboxylate ions from C2 to C16 have been deuterated in the α position. The α-C—D bond axis in the solubilisate increases in order with chain length, the anion having lower order than the parent acid. An accurately linear increase in the degree of order of the α position is observed for intermediate chain lengths. At chain lengths approximately equal to the host chain lengths the α position reaches a limiting value in the degree of order and further segments do not influence the order. At short chain lengths the degree of order is less than that predicted from extrapolation of order in the linear region. This has been interpreted in terms of distribution into the aqueous compartment by the solubilisates of short chain length. Acetic acid and the acetate, propionate, butanoate, and pentanoate ions spend an appreciable amount of time in the aqueous region. An estimate has been made of these distributions based on reasonable assumptions.

scholarly journals Changes of Membrane Fluidity in Erythrocytes of Obese Children: A Spin Label Study

1987 ◽  
Vol 22 (2) ◽  
pp. 141-144 ◽  
Author(s):  
Giovanna Curatola ◽  
Gianna Ferretti ◽  
Enrico Bertoli ◽  
Maria Dotti ◽  
Edoardo Bartolotta ◽  
...  
Keyword(s):  
Membrane Fluidity ◽  
Spin Label ◽  
Obese Children ◽  
Label Study

A spin-label study of membrane proteins and internal microviscosity of erythrocytes in hereditary spherocytosis

Life Sciences ◽  
1987 ◽  
Vol 41 (20) ◽  
pp. 2285-2288 ◽  
Author(s):  
G. Bartosz ◽  
M. Gaczyńska ◽  
E. Grzelińska ◽  
L. Judkiewicz
Keyword(s):  
Membrane Proteins ◽  
Spin Label ◽  
Hereditary Spherocytosis ◽  
Label Study
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