Mixed‐chain phospholipids: Structures and chain‐melting behavior

Huang, Chunbo

doi:10.1007/s11745-001-0818-1

Cited by 49 publications

(33 citation statements)

References 27 publications

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“…1, C and D). Thus, the T m of a lipid bilayer strongly correlates to the acyl chain structure (12). These data also illustrate the general observation that the introduction of double bonds cause increased disorder and thus lowers the T m .…”

Section: Introductionsupporting

confidence: 73%

“…These single-lipid samples were chosen as they are well-characterized and have well-known T m values determined by various different methods (12)(13)(14). The selected lipid types reflect a range of T m values: near room temperature (DMPC), near water's normal freezing point (SOPC and POPC), and significantly below zero degrees Celsius (OPPC).…”

Section: Lipid and Solvent Freezing For Single-lipid Vesiclesmentioning

confidence: 99%

“…Although a lipid's T m depends on both the type of lipid head group and the identity of the attached acyl chains (Fig. 1), it is well-established that the acyl chains have a particularly prominent effect (12,13). Despite having different headgroups (in both charge and size), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) have similar T m values of 41.3 C and 41.5 C, respectively (Fig.…”

Section: Introductionmentioning

confidence: 99%

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MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

Mandal

Wel

2016

Biophysical Journal

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The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS 1 H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (T m ). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.

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Section: Introductionsupporting

confidence: 73%

Section: Lipid and Solvent Freezing For Single-lipid Vesiclesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

Mandal

Wel

2016

Biophysical Journal

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“…This decreases the cooperativity of the chain interactions and causes a substantial decline in the main phase transition temperature (13,(15)(16)(17)(18). The effect of a trans double bond on the main phase transition temperature of hydrocarbon chains is much weaker (13,16,18).…”

mentioning

confidence: 99%

Effects of phospholipid unsaturation on the bilayer nonpolar region

Róg

Murzyn

Gurbiel

et al. 2004

Journal of Lipid Research

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Molecular dynamics simulations of two monounsaturated phosphatidylcholine (PC) bilayers made of 1-palmitoyl-2-oleoyl-PC (POPC; cis -unsaturated) and 1-palmitoyl-2-elaidoyl-PC (PEPC; trans -unsaturated) were carried out to investigate the effect of a double bond in the PC ␤ -chain and its conformation on the bilayer core. Four nanosecond trajectories were used for analyses. A fully saturated 1,2-dimyristoyl-PC (DMPC) bilayer was used as a reference system. In agreement with experimental data, this study shows that properties of the PEPC bilayer are more similar to those of the DMPC than to the POPC bilayer. The differences between POPC and PEPC bilayers may be attributed to the different ranges of angles covered by the torsion angles ␤ 10 and ␤ 12 of the single bonds next to the double bond in the oleoyl (O) and elaidoyl (E) chains. Broader distributions of ␤ 10 and ␤ 12 in the E chain than in the O chain make the E chain more flexible. In effect, the packing of chains in the PEPC bilayer is similar to that in the DMPC bilayer, whereas that in the POPC bilayer is looser than that in the DMPC bilayer. The effect of the cis -double bond on torsions at the beginning of the O chain ( ␤ 4 and ␤ 5) is similar to that of cholesterol on these torsions in a myristoyl chain. Phospholipids with two asymmetric hydrocarbon chains, of which one is fully saturated in the ␥ position and the other is mono-cis -or poly-cis -unsaturated in the ␤ position, are the most common in nature (1). Among mono-cisunsaturated phosphatidylcholines (PCs), 1-palmitoyl-2-oleoyl-PC (POPC) is the most abundant. In the past, phospholipids with trans -unsaturated hydrocarbon chains were believed to be rare in nature. They were found in photosynthetic membranes of higher plants (2) and algae (3) as well as in some marine bacteria (4). With advances in separation and quantification techniques, new trans -unsaturated lipids have been identified in membranes of prokaryotes (5) and algal chloroplasts (6). In membranes of gram-negative bacteria, the relative proportion of transunsaturated lipids increases under physiologically stressful conditions, such as increased temperature (7), starvation and desiccation (8), and organic solvents (9). The increase of the trans -to-cis ratio results from an enzymatically controlled direct cis -trans isomerization that does not shift the position of the double bond and occurs only at the ␤ position of the glycerol moiety (7). The cis -trans conversion in the bacterial membrane is believed to be a fast and inexpensive mechanism enabling the membrane to maintain constant fluidity (5).Experimental (10-13) and molecular modeling (14) studies of model membranes show that in the membrane, a double bond in the cis conformation located near the middle of the chain interferes with the hydrocarbon chain packing. This decreases the cooperativity of the chain interactions and causes a substantial decline in the main phase transition temperature (13,(15)(16)(17)(18). The effect of a trans double bond on the main phase trans...

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“…In some cases, it is desirable to have well-defined PL products having a specified fatty acid in one or both positions. Using enzymatic acyl exchange, the desired physical properties and special functions can be achieved [2]. Incorporation of medium-chain fatty acids into PL provides heat stability [3].…”

Section: Introductionmentioning

confidence: 99%

Enzymatic acyl modification of phosphatidylcholine using immobilized lipase and phospholipase A₂

Pandit

2010

Euro J Lipid Sci & Tech

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Ethanol-soluble (ES) lecithin mainly contains phosphatidylcholine (PC). The incorporation of caprylic acid into PC using immobilized phospholipase A 2 (PLA 2 ) and lipase was investigated. The Rhizomucor meihei lipase and the porcine pancreatic PLA 2 were immobilized on the hydrophobic resin Diaion HP-20 and the modification was carried out in hexane as solvent. HPTLC with densitometer technique was successfully used for monitoring the production of structured phospholipids (PL) (ML-type PC, MM-type PC, and lysophosphatidylcholine; L: long-chain fatty acid, M: medium-chain fatty acid). The various parameters such as the effects of reaction temperature, enzyme loading, and the effect of molar proportion of substrate were studied in order to determine the optimum reaction conditions for the acidolysis reaction. The optimal operating conditions for the PLA 2 -catalyzed reaction were obtained as 508C temperature, 50% (wt/wt of substrate) enzyme loading, and a 1:12 molar proportion of PC/caprylic acid. For the lipase-catalyzed reaction, the optimized temperature was the same as for PLA 2 , but the enzyme loading and molar proportion were slightly lower, i.e., 40 % w/w of substrate and 1:9 PC/caprylic acid, respectively. The effects of these parameters on the production of structured PL were compared. Under these optimal conditions, the ML-type PC content was higher in the PLA 2 -catalyzed reaction, i.e., 45.29 mol%, and in the lipase-catalyzed reaction it was 38.74 mol%.

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Mixed‐chain phospholipids: Structures and chain‐melting behavior

Cited by 49 publications

References 27 publications

MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

Effects of phospholipid unsaturation on the bilayer nonpolar region

Enzymatic acyl modification of phosphatidylcholine using immobilized lipase and phospholipase A₂

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Mixed‐chain phospholipids: Structures and chain‐melting behavior

Cited by 49 publications

References 27 publications

MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

MAS 1 H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes

Effects of phospholipid unsaturation on the bilayer nonpolar region

Enzymatic acyl modification of phosphatidylcholine using immobilized lipase and phospholipase A2

Contact Info

Product

Resources

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Enzymatic acyl modification of phosphatidylcholine using immobilized lipase and phospholipase A₂