A calorimetric investigation of a series of mixed-chain polyunsaturated phosphatidylcholines: effect of sn-2 chain length and degree of unsaturation

Niebylski, Charles D.; Salem, Norman

doi:10.1016/s0006-3495(94)80725-8

Cited by 67 publications

(63 citation statements)

References 28 publications

(41 reference statements)

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“…The area/molecule for a series of 18:0-XPCs where X represents acyl chains with 0 to 6 double bonds was shown to increase dramatically upon the addition of a first, second and third double bond, but does not change significantly with subsequent double bonds [68]. Interestingly this pattern of a large alteration caused by the addition of a first few double bonds but little further change with subsequent double bonds is qualitatively analogous to that reported for "fluidity" as detected by steady state fluorescence depolarization and membrane order as probed by 2 H NMR of the perdeuterated [ 2 H 35 ]18:0 sn-1 chain [45], and for main melting transition temperature (T m ) as measured by DSC (differential scanning calorimetry) [57,66] and moment analysis of solid state 2 H NMR spectra [45].…”

Section: Lipid Packing and Elasticitysupporting

confidence: 79%

“…Pressure-area curves for PC monolayer films at the air-water interface demonstrate that, as anticipated, the cross-sectional area generally increases with increasing double bonds and is particularly large in the presence of DHA [66,67]. The area/molecule for a series of 18:0-XPCs where X represents acyl chains with 0 to 6 double bonds was shown to increase dramatically upon the addition of a first, second and third double bond, but does not change significantly with subsequent double bonds [68].…”

Section: Lipid Packing and Elasticitysupporting

confidence: 72%

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Docosahexaenoic acid affects cell signaling by altering lipid rafts

et al. 2005

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-With 22 carbons and 6 double bonds docosahexaenoic acid (DHA) is the longest and most unsaturated fatty acid commonly found in membranes. It represents the extreme example of a class of important human health promoting agents known as omega-3 fatty acids. DHA is particularly abundant in retinal and brain tissue, often comprising about 50% of the membrane's total acyl chains. Inadequate amounts of DHA have been linked to a wide variety of abnormalities ranging from visual acuity and learning irregularities to depression and suicide. The molecular mode of action of DHA, while not yet understood, has been the focus of our research. Here we briefly summarize how DHA affects membrane physical properties with an emphasis on membrane signaling domains known as rafts. We report the uptake of DHA into brain phosphatidylethanolamines and the subsequent exclusion of cholesterol from the DHA-rich membranes. We also demonstrate that DHA-induced apoptosis in MDA-MB-231 breast cancer cells is associated with externalization of phosphatidylserine and membrane disruption ("blebbing"). We conclude with a proposal of how DHA incorporation into membranes may control cell biochemistry and physiology. apoptosis / docosahexaenoic acid / lipid rafts / membranes / phospholipids

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Section: Lipid Packing and Elasticitysupporting

confidence: 79%

Section: Lipid Packing and Elasticitysupporting

confidence: 72%

Docosahexaenoic acid affects cell signaling by altering lipid rafts

et al. 2005

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supporting

confidence: 77%

“…Interestingly, the introduction of a third cis double bond between the second cis double bond and the methyl end can cause a slight increase in T m . This calorimetric work has been confirmed more or less by other investigators using PCs with different chain lengths (7,8).Recently, we have studied systematically the effect of different positions of single cis double bond in the sn-2-acyl chain on the phase transition behavior of lipid bilayers composed of sn-1 saturated/sn-2-monounsaturated PCs or phosphatidylethanolamines (PEs) by high resolution DSC and computer-based molecular mechanics (MM) simulations (9 -11). The position of the single cis double bond (⌬ n ) is found in both lipid classes to exert a characteristic influence on the gel-to-liquid crystalline…”

supporting

confidence: 77%

Influence of the Positions of cis Double Bonds in the sn-2-Acyl Chain of Phosphatidylethanolamine on the Bilayer's Melting Behavior

Huang

Huo

et al. 1997

Journal of Biological Chemistry

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In an attempt to examine the effects of different numbers and positions of cis double bonds in the sn-2-acyl chain of phosphatidylethanolamine (PE) on the bilayer's melting behavior, 21 molecular species of PE were first semisynthesized, and their T m and ⌬H values were subsequently determined by high resolution differential scanning calorimetry. In the plot of T m versus the number of the cis double bond, some characteristic profiles were observed for the various series of PEs. In recent years, there has been increasing evidence suggesting the existence of a close correlation between some vital functions of cells and the various degrees of unsaturation in the sn-2-acyl chains of membrane phospholipids (1-3). Consequently, detailed and systematic investigation of the properties of sn-1-saturated/sn-2-unsaturated phospholipids in the organized membrane structure such as the lipid bilayer should be recognized and pursued. Furthermore, now is the time for studying unsaturated phospholipids, since sophisticated computer-based molecular modeling techniques from the hardware and the software fields have come together to provide valuable structural and energetic information about self-assembled biomolecules within a reasonable time frame. Results obtained with experimental and modeling studies of sn-1-saturated/sn-2-unsaturated phospholipids could eventually help illuminate the specific roles played by various natural phospholipids in many membrane-related cell functions or diseases.The first detailed and systematic studies of the thermotropic phase behavior of phospholipids containing various numbers of cis double bonds in their sn-2-acyl chains were performed by Keough and co-workers (4 -6). By using two series of phosphatidylcholines (PCs) 1 and by applying the differential scanning calorimetry (DSC) techniques, they have shown that the introduction of a cis double bond into the sn-2-acyl chain at or near the center of the chain has a marked reducing effect on the phase transition temperature (T m ) associated with the gel-toliquid crystalline phase transition of the lipid bilayer. A second cis double bond incorporated at the methylene-interrupted position toward the methyl end also reduces the T m , but by a smaller amount. Interestingly, the introduction of a third cis double bond between the second cis double bond and the methyl end can cause a slight increase in T m . This calorimetric work has been confirmed more or less by other investigators using PCs with different chain lengths (7,8).Recently, we have studied systematically the effect of different positions of single cis double bond in the sn-2-acyl chain on the phase transition behavior of lipid bilayers composed of sn-1 saturated/sn-2-monounsaturated PCs or phosphatidylethanolamines (PEs) by high resolution DSC and computer-based molecular mechanics (MM) simulations (9 -11). The position of the single cis double bond (⌬ n ) is found in both lipid classes to exert a characteristic influence on the gel-to-liquid crystalline

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“…Interestingly, the introduction of a third cis double bond at C (17) results in a small increase in T m for C (20):C(20:3⌬ 11,14,17 )PC. This down and up trend in T m has been confirmed calorimetrically by other groups (4,5). One can immediately raise a relevant question as to whether this down and up T m profile is a special or a general characteristic for acyl chain unsaturation.…”

supporting

confidence: 60%

Effects of Various Numbers and Positions of cisDouble Bonds in the sn-2 Acyl Chain of Phosphatidylethanolamine on the Chain-melting Temperature

Wang

Huo

et al. 1999

Journal of Biological Chemistry

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In an attempt to investigate systematically the effects of various single and multiple cis carbon-carbon double bonds in the sn-2 acyl chains of natural phospholipids on membrane properties, we have de novo synthesized unsaturated C 20 fatty acids comprised of single or multiple methylene-interrupted cis double bonds. Subsequently, 15 molecular species of phosphatidylethanolamine (PE) with sn-1 C 20 -saturated and sn-2 C 20 -unsaturated acyl chains were semi-synthesized by acylation of C 20 -lysophosphatidylcholine with unsaturated C 20 fatty acids followed by phospholipase D-catalyzed base-exchange reaction in the presence of excess ethanolamine. The gel-to-liquid crystalline phase transitions of these 15 mixed-chain PE, in excess H 2 O, were investigated by high resolution differential scanning calorimetry. In addition, the energy-minimized structures of these sn-1 C 20 -saturated/sn-2 C 20 -unsaturated PE were simulated by molecular mechanics calculations. It is shown that the successive introduction of cis double bonds into the sn-2 acyl chain of C(20):C(20)PE can affect the gel-to-liquid crystalline phase transition temperature, T m , of the lipid bilayer in some characteristic ways; moreover, the effect depends critically on the position of cis double bonds in the sn-2 acyl chain. Specifically, we have constructed a novel T m diagram for the 15 species of unsaturated PE, from which the effects of the number and the position of cis double bonds on T m can be examined simultaneously in a simple, direct, and unifying manner. Interestingly, the characteristic T m profiles exhibited by different series of mixed-chain PE with increasing degree of unsaturation can be interpreted in terms of structural changes associated with acyl chain unsaturation.Most naturally occurring diacyl phospholipids in eukaryotic cell membranes are of a mixed acyl chain variety, meaning that the fatty acids esterified at the sn-1 and sn-2 positions of the glycerol backbone are originated primarily in vivo from saturated and unsaturated fatty acyl-CoA, respectively. Since the chemical composition of fatty acids can vary greatly in terms of the acyl chain length, the degree of unsaturation, and the position of cis carbon-carbon double bonds (⌬-bonds), 1 membrane phospholipids are structurally an extremely diverse group of amphipathic molecules. In a given type of cell, membrane phospholipids may amount to several hundreds of distinctive chemical species. Despite the bewildering diversity, the basic motif of most unsaturated fatty acyl chains is surprisingly simple, viz. in the sn-2 acyl chain, the cis carboncarbon double bonds are invariably separated by a three-carbon unit comprised of a methylene group (-CH 2 -) sandwiched by two olefinic carbons. The biochemical significance of this regular methylene-interrupted interval is, however, not clear.Although it has long been known that mixed-chain diacyl phospholipids in aqueous media can uniquely assemble into a two-dimensional sheet-like structure called the lipid bilayer, progress is non...

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A calorimetric investigation of a series of mixed-chain polyunsaturated phosphatidylcholines: effect of sn-2 chain length and degree of unsaturation

Cited by 67 publications

References 28 publications

Docosahexaenoic acid affects cell signaling by altering lipid rafts

Docosahexaenoic acid affects cell signaling by altering lipid rafts

Influence of the Positions of cis Double Bonds in the sn-2-Acyl Chain of Phosphatidylethanolamine on the Bilayer's Melting Behavior

Effects of Various Numbers and Positions of cisDouble Bonds in the sn-2 Acyl Chain of Phosphatidylethanolamine on the Chain-melting Temperature

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