Studies on the hydrogen belts of membranes: I. Diester, diether, and dialkyl phosphatidylcholines and polyoxyethylene glycerides in monolayers with cholesterol

Fong, J. W.; Tirri, Lawrence J.; Deshmukh, Diwakar S.; Brockerhoff, H.

doi:10.1007/bf02533276

Cited by 38 publications

(12 citation statements)

References 19 publications

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“…It has been proposed in the past that the sterol hydroxyl group would play an essential role in hydrogen bridge formation between sterol and phospholipid [30][31][32]. There is, however, no experimental support for a direct interaction between phospholipid and sterol.…”

Section: Discussionmentioning

confidence: 99%

The effect of the sterol oxygen function on the interaction with phospholipids

Demel

Lala

Kumari

et al. 1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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The effect of cholesteryi ethers (namely cholesteryl methyl ether, cholesteryi ethyl ether, cholesteryl n-propyl ether, cholesteryi isopropyl ether, cholesteryi butyl ether, cholesteryl methoxymethyl ether, cholesteryl (2'-hydroxy)-3-ethyl ether) and cholesteryl ester (namely cholesteryi acetate) is tested on the interaction with phosphatidylcholines in liquid-crystalline and crystalline state. The interfacial properties of sterols are tested at the air-water interface. The cholesteryl ethers show a reduced interracial stability with increasing hydrophobicity of the ether-linked moiety. The interaction between the sterol derivatives and phospholipids in mixed monolayers is indicated by measuring the deviation from the simple addivity rule (condensing effect). An interaction is found only for cholesteryl (2'-hydroxy)-3-ethyl ether, cholesteryl methyl ether and cholesteryl ethyl ether. These sterols also reduce the glucose permeability of liposomal membranes in this order. In this respect cholesteryl (2'-hydroxy)-3-ethyl ether is as effective as cholesterol. Cholesteryl methyl ether and cholesteryl ethyl ether show 62 and 33 percent of the effect observed with cholesterol. The effect of the sterol derivatives on the gel-to-liquid-crystalline phase transition of dipalmitoylphosphatidylcholine is measured by differential scanning calorimetry. Cholesteryl methyl ether, cholesteryl ethyl ether, and cholesteryl (2'-hydroxy)-3-ethyl ether reduce the energy content of the phase transition nearly as effective as cholesterol, cholesteryl n-propyl ether has only a small effect. Although cholesteryl acetate, and cholesteryl methoxymethyl ether have no condensing or permeability-reducing effect, they have a considerable effect on the gel-to-liquid-crystalline phase transition. Cholesteryi isopropyl ether and cholesteryl butyl ether have no effect. It is concluded that a free 30-hydroxy group is not a prerequisite to observe a sterol-like effect in membranes. However, the interfacial stability and the orientation of the sterol and oxygen moiety at the sterol 3-position are important.

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Section: Discussionmentioning

confidence: 99%

The effect of the sterol oxygen function on the interaction with phospholipids

Demel

Lala

Kumari

et al. 1984

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…Our results contrast with those , who calculated a reduction of about 5 kcal mol"1 in activation energy and -16 cal mol"1 deg"1 in activation entropy for glycerol and urea permeation into diether-PC bilayers upon incorporation of cholesterol. Although the condensation effect of cholesterol was observed in monolayers of PC analogues lacking the carbonyl group (Fong et al, 1977), it was speculated that hydrogen bonding between the phospholipid carbonyl oxygen atom and the hydrogen of the cholesterol hydroxyl group is important in bilayers (Tirri et al, 1977). Schwarz & Paltauf (1977) reported that the rates of diffusion of Na+, Cl", and glucose across vesicles prepared from a diether-PC were not affected by incorporation of cholesterol to 30 mol % and suggested that the carbonyl oxygens may be required for PC-cholesterol interaction; however, cholesterol reduced the freedom of motion of a fatty acid spin probe to a similar extent in liposomes formed from each PC (Schwarz & Paltauf, 1977).…”

Section: Discussionmentioning

confidence: 99%

Permeability properties of sterol-containing liposomes from analogs of phosphatidylcholine lacking acyl groups

Clejan¹,

Bittman²,

Deroo³

et al. 1979

Biochemistry

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The effect of sterols on the rates of nonelectrolyte movement in multilayered liposomal membranes formed from various phosphatidylcholine (PC) analogues was studied. We measured the temperature dependence of the permeation of small, polar solutes through lipid bilayers in the liquidcrystalline state of the following saturated phosphatidylcholines: diesters containing 14, 16, or 18 carbon atoms in each acyl chain; the corresponding diethers, which lack the carbonyl groups; and alkyl analogues, such as 2-octadecyleicosylphosphorylcholine (OEPC), which have no diacylglycerol or glycerol diether moiety. In addition, a diether-PC having one saturated and one unsaturated chain was used, and analogues of OEPC were synthesized in which the choline group is modified. At temperatures above the gel to liquid-crystalline phase transition of these diester, diether, and alkyl analogues of PC, the 30-hydroxysteroids cholesterol and ergosterol decreased the permeability of glycerol, urea, acetamide, and glucose, whereas epicholesterol and lanosterol exerted little effect on the reflection coefficient for acetamide penetration. Cholesterol reduced solute permeability in liposomes from OEPC analogues having increased separation

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“…The ester linkage was found necessary for the permeability decrease produced by cholesterol in one study (88) but not in another study (89). Although the ester linkage may not be required for the effect of cholesterol on lipids, intermolecular hydrogen bonding may nevertheless occur (55). It would not result in a hydrogen-bonding network, however, and might even have the effect of breaking up such a network since it could only form a binary complex with another lipid.…”

Section: Hydrogen Bonding Of Lipids To Cholesterolmentioning

confidence: 93%

Intermolecular hydrogen bonding between lipids: influence on organization and function of lipids in membranes

Boggs¹

1980

Can. J. Biochem.

237

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Biological membranes have unique lipid compositions suggesting a specific role for many lipids. Evidence is reviewed concerning the intermolecular forces between glycero- and sphingolipids and cholesterol, the dependence of many of these interactions on the state of ionization of lipids, pH, ionic strength, and divalent cation concentration. The effect of intermolecular interactions between certain lipids on lipid clustering, interaction with cholesterol, on the conformation of proteins, and on transitions to the hexagonal phase is considered. Other forces which cause lipids phase separation or clustering are discussed. It is concluded that lipids are in dynamic equilibrium with their environment and can act as receptors for certain intra- or extra-cellular stimuli, which they can translate into a response by undergoing changes in fluidity, phase transitions, or phase separation.

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Studies on the hydrogen belts of membranes: I. Diester, diether, and dialkyl phosphatidylcholines and polyoxyethylene glycerides in monolayers with cholesterol

Cited by 38 publications

References 19 publications

The effect of the sterol oxygen function on the interaction with phospholipids

The effect of the sterol oxygen function on the interaction with phospholipids

Permeability properties of sterol-containing liposomes from analogs of phosphatidylcholine lacking acyl groups

Intermolecular hydrogen bonding between lipids: influence on organization and function of lipids in membranes

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