NMR differentiation of the internal and external phospholipid membrane surfaces using paramagnetic Mn2+ and Eu3+ ions

Bystrov, V. F.; Дубровина, Н. И.; Barsukov, L.I.; Bergel'son, L. D.

doi:10.1016/0009-3084(71)90046-6

Cited by 160 publications

(53 citation statements)

References 10 publications

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“…A significant fraction (0.34) of the choline resonance is unshifted; therefore, about a third of the choline groups are protected from approach of the Eu3+. These results are very similar to those reported for sealed PtdCho vesicles (13), and indicate that most, if not all, of the recombinant vesicles are sealed to Eu3+ in the dark. Similar results were obtained with the 1:200 recombinant and EuC13.…”

supporting

confidence: 80%

“…lb). In accordance with previous observations about paramagnetic shift reagents and PtdCho vesicles (13,14), the upfield peak is assigned to the choline groups, which are in close proximity to the paramagnetic ions. If all of the vesicles are sealed, only the choline groups on the outside of the vesicles are shifted.…”

supporting

confidence: 65%

“…These rhodopsin:phospholipid preparations are likely candidates for the examination of light-initiated transmitter release. In this study, we have utilized proton and phosphorus nuclear magnetic resonance (NMR) spectroscopy to examine unexposed and bleached rhodopsin:phospholipid recombinant membranes in the presence and absence of selected shift (13) and relaxation (14) agents and have found evidence for lightinduced ion translocation across the membranes. EXPERIMENTAL Materials.…”

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confidence: 99%

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Light-regulated permeability of rhodopsin:egg phosphatidylcholine recombinant membranes.

O’Brien¹,

Zumbulyadis²,

Michaels³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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Purified rhodopsin was incorporated into phospholipid bilayers of egg phosphatidylcholine to give recombinant membrane vesicles, which were examined by proton and phosphorus nuclear magnetic resonance spectroscopy. Increased rhodopsin content in the membranes appears to progressively inhibit the molecular motions of the methyl, methylene, and phosphate groups of the phospholipid molecules. This indicates that regions of the rhodopsin molecule interact in a manner that affects the phospholipids from the aqueous interface to the bilayer midline. In the dark, the recombinant vesicles were sealed to europium, manganese, or cobalt ions. Light exposure allowed rapid equilibration of Mn2+ and Co2+, and somewhat slower equilibration of Eu3+ across the membrane. Light changed the membrane permeability, and the gradient in chemica tential resulted in a net ion movement across the rhodopsin:phospholipid recombinant membrane. The results suggest rhodopsin is a transmembrane protein.

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supporting

confidence: 80%

supporting

confidence: 65%

mentioning

confidence: 99%

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Light-regulated permeability of rhodopsin:egg phosphatidylcholine recombinant membranes.

O’Brien¹,

Zumbulyadis²,

Michaels³

et al. 1977

Proc. Natl. Acad. Sci. U.S.A.

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“…Most of these studies, however, are concerned primarily with the mobility of fatty acyl chains of the bilayer (2, 3). As reported several times (4)(5)(6), paramagnetic ions such as europium (Eug+) added to the exterior of lipid vesicles shift the field position of the -N+(CHI3)3 protons of phosphatidylcholine (PC) molecules that reside on the outer surface of lipid vesicles, which are closed shelllike spheres of about 250 X in diameter, each comprised of a single, continuous, lipid-bilayer membrane enclosing a volume of aqueous solution (7). Using these paramagnetic ions as shift markers, the head groups in the two halves of vesicle bilayers can be spectrally identified.…”

supporting

confidence: 58%

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Huang

Sipe

Chow

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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The Proton nuclear magnetic resonance (PMR) spectroscopy has been applied extensively in recent years to elucidate the structural or conformational properties of phospholipids and biomembranes (1). Most of these studies, however, are concerned primarily with the mobility of fatty acyl chains of the bilayer (2, 3). As reported several times (4-6), paramagnetic ions such as europium (Eug+) added to the exterior of lipid vesicles shift the field position of the -N+(CHI3)3protons of phosphatidylcholine (PC) molecules that reside on the outer surface of lipid vesicles, which are closed shelllike spheres of about 250 X in diameter, each comprised of a single, continuous, lipid-bilayer membrane enclosing a volume of aqueous solution (7). Using these paramagnetic ions as shift markers, the head groups in the two halves of vesicle bilayers can be spectrally identified. Consequently, the application of PMR technique has now been extended to investigate the structural properties of the outer and (or) inner polar head regions of the bilayer. The interaction of phospholipid with cholesterol in the bilayer structure has been studied recently by a variety of physical techniques (8-10). On the basis of these studies, it has been proposed that the effect of cholesterol on phospholipids in the bilayer structure is to restrict differentially the number of steric conformations accessible to the segments of the fatty acyl chains (11). However, more recent studies have shown that the 3,8-OH group of cholesterol is also of crucial importance for phospholipid-sterol interaction (12, 13), and, as a consequence, interactions in the polar head regions of the bilayer should be examined further.In this preliminary communication, we report the effects of cholesterol content on the -N+(CH3)3 proton resonance signal of the vesicle bilayer in the presence of a paramagnetic lanthanide ion, praseodymium ion (Pr'+). We chose Pr'+ rather than Eu8+ as a shift marker to study differentially the two polar head regions of the vesicle bilayer because, at a lower concentration, the Pr'+ ions produced at greater spectral splitting of the -N+(CH3)3 resonance signal upon coordination with the polar head groups of the bilayer. EXPERIMENTAL MATERIALS AND PROCEDURESCholesterol was obtained from Sigma Co., St. Louis, Mo., and further purified through bromination according to the method of Schwenk and Werthessen (14). L-a-Dipalmitoyl PC was purchased from Calbiochem, La Jolla, Calif. Egg PC was isolated and purified as described previously (7)

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“…A 31P ety extending down into the bilayer interior. When nmr-lanthanide shift reagent technique was emselectively deuterated CP in an egg phosphatidyl-ployed (8). Addition of the shift reagent to a sonicholine multilamellar liposome system was studied cated dispersion separates the 31P resonances from using ZH nmr spectroscopy, a smaller fraction of the inside and outside surfaces of the vesicles, and, added ester (-0.2 mol%) was found to intercalate from the relative intensity of the signals, an average between egg phosphatidylcholine molecules (5).…”

Section: Introductionmentioning

confidence: 99%

Deuterium and phosphorus-31 nuclear magnetic resonance of cholesteryl palmitate in dipalmitoylphosphatidylcholine model membranes

Cushley¹,

Gorrissen²,

Wassall³

1980

Can. J. Chem.

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Dedicated to Prof. Raymond U. Lemieux on the occasion of his 60th birthday ROBERT J. CUSHLEY, HEINERGORRISSEN, and STEPHEN R. WASSALL. Can. J. Chem. 58,2433Chem. 58, (1980. Cholesteryl palmitate (CP) has been incorporated into vesicles of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylcholine/20 mol% cholesterol, in amounts up to 5 mol%. By means of 3'P lanthanide induced shifts the average diameter of these vesicles was calculated to be -270 A.The 2H spectral linewidths of selectively deuterated CP incorporated into liquid crystalline dipalmitoylphosphatidylcholine vesicles are S 150 Hz, implying a low degree of order for the ester acyl chain. Addition of 20 mol% cholesterol to the vesicles increases the linewidths which, nevertheless, remain 5 185 Hz. The corresponding 2H longitudinal relaxation times (1450 ms) indicate that the fast segmental motions of the ester chain are slower than for the phospholipid chains.ROBERT J. CUSHLEY, HEINER GORRISSEN et STEPHEN R. WASSALL. Can. J. Chem. 58,2433Chem. 58, (1980. On a incorpore le palmitate de cholesteryle (PC) en quantite allant jusqu'i 5 mol% dans les vesicules de dipalmitoylphosphatidylcholine et de dipalmitoylphosphatidylcholine/20 mol% cholesterol. Au moyen des deplacements chimiques du )'P induits par les lanthanides on a calculk que le diambtre moyen de ces vesicules est d'environ 270 A. Les largeurs des raies des spectres rmn 2H des PC deuteres selectivement et incorpores dans les vCsicules de dipalmitoylphosphatidylcholine cristallins B I'etat liquide sont S 150 Hz; ceci implique un faible degre d'ordre de la chaine ester acyc1ique.L'addition de 20 mol% de cholest6rol aux vesicules augmente la largeur des raies qui nkanmoins restent i 185 Hz. Les temps de relaxation longitudinale correspondants du 2H (2450 ms) indiquent que les rapides mouvements des segments de la chaine ester sont plus lents que ceux des chaines phospholipides.[Traduit par le journal] Introduction the phospholipid is changed from phosphatidylWe have been studying the structure and proper-choline to sphingomyelin the amount of interties of cholesteryl esters in various phospholipid calated CP reaches 1.5 mol% (7). membrane systems using a diversity of magnetic When eggphosphatidylcholine bilayers are made resonance techniques. In our initial study (1) we by sonication of aqueous dispersions to form highly utilized 31P nmr spectroscopy and found that curved unilamellar vesicles, ester intercalation incholesteryl palmitate (CP) increased the permea-creases substantially, reaching as high as 5 mol% bility of model membranes to ions, whereas (6) while the ester chains appear more disordered cholesteryl linoleate did not. The behavior of the compared to CP in multilamellar liposomes (5). saturated ester CP in egg phosphatidylcholineThe present study is an attempt to determine the bilayer systems was studied by epr of spin-labeled behavior of saturated cholesteryl ester in a highly CP in multilayers (2, 3), as well as 13C nmr differ-curved bilayer composed of the completely satuenc...

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NMR differentiation of the internal and external phospholipid membrane surfaces using paramagnetic Mn2+ and Eu3+ ions

Cited by 160 publications

References 10 publications

Light-regulated permeability of rhodopsin:egg phosphatidylcholine recombinant membranes.

Light-regulated permeability of rhodopsin:egg phosphatidylcholine recombinant membranes.

Differential Interaction of Cholesterol with Phosphatidylcholine on the Inner and Outer Surfaces of Lipid Bilayer Vesicles

Deuterium and phosphorus-31 nuclear magnetic resonance of cholesteryl palmitate in dipalmitoylphosphatidylcholine model membranes

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