IR spectroscopic determination of gel state miscibility in long-chain phosphatidylcholine mixtures

Mendelsohn, R.; Liang, Guangxin; Strauss, Herbert L.; Snyder, Robert

doi:10.1016/s0006-3495(95)80069-x

Cited by 64 publications

(43 citation statements)

References 23 publications

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“…2). A similar pattern of spectroscopic change was observed in recent studies involving long-chain PC bilayers and mixtures thereof (Mendelsohn et al, 1995; Snyder et al, submitted for publication). The latter authors attribute this behavior to thermally induced interconversions between two different gel phases, both with orthorhombically packed hydrocarbon chains (designated G. and Gd;…”

Section: Resultssupporting

confidence: 86%

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The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs

Lewis

Pohle

McElhaney

1996

Biophysical Journal

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The thermotropic phase behavior of aqueous dispersions of dipalmitoylphosphatidylcholine (DPPC) and its 1,2-dialkyl, 1-acyl 2-alkyl and 1-alkyl 2-acyl analogs was examined by differential scanning calorimetry, and the organization of these molecules in those hydrated bilayers was studied by Fourier transform infrared spectroscopy. The calorimetric data indicate that substitution of either or both of the acyl chains of DPPC with the corresponding ether-linked hydrocarbon chain results in relatively small increases in the temperature (< 4 degrees C) and enthalpy (< 1 kcal/mol) of the lipid chain-melting phase transition. The spectroscopic data reveal that replacement of one or both of the ester-linked hydrocarbon chains of DPPC with its ether-linked analog causes structural changes in the bilayer assembly, which result in an increase in the polarity of the local environments of the phosphate headgroups and of the ester carbonyl groups at the bilayer polar/apolar interface. The latter observation is unexpected, given that ester linkages are considered to be intrinsically more polar that ether linkages. This finding cannot be satisfactorily rationalized unless the conformation of the glycerol backbones of the analogs containing ether-linked hydrocarbon chains differs significantly from that of diacyl glycerolipids such as DPPC. A comparison of the alpha-methylene scissoring bands and the methylene wagging band progressions of these lipids with the corresponding absorption bands of specifically chain-perdeuterated analogs of DPPC also supports the conclusion that replacement of the ester-linked hydrocarbon chains of DPPC with the corresponding ether-linked analog induces conformational changes in the lipid glycerol backbone. The suggestion that the conformation of glycerol backbones in the alkyl-acyl and dialkyl derivatives of DPPC differs from that of the naturally occurring 1,2-diacyl glycerolipid suggests that mono- and di-alkyl glycerolipids may not be good models of their diacyl analogs. These results, and previously published evidence that DPPC analogs with ether-linked hydrocarbon chains spontaneously form chain-interdigitated gel phases at low temperatures, clearly indicate that the properties of lipid bilayers can be substantially altered by small changes in the chemical structures of their polar/polar interfaces, and highlight the critical role of the interfacial region as a determinant of the structure and organization of lipid assemblies.

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Section: Resultssupporting

confidence: 86%

“…see Mendelsohn et al, 1995; al., submitted for publication). Interestingly, with DHPC this thermally induced change in the magnitude of the correlation field splitting coincides with the calorimetrically detectable but weakly endothermic event that was alluded to earlier.…”

Section: Resultsmentioning

confidence: 99%

The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs

Lewis

Pohle

McElhaney

1996

Biophysical Journal

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“…The magnitude of the splitting between the two deformation mode correlation field components is proportional to the number of interacting chains. Snyder and Mendelsohn demonstrated that domains consisting of different length saturated lipids exhibited temperature-dependent segregation properties from single molecules to microaggregates of up to 100 molecules (30,31). The kinetics of domain formation was reported in a ceramide/ fatty acid/cholesterol stratum corneum model system using this approach (32).…”

Section: Introductionmentioning

confidence: 94%

Lipid Microdomain Formation: Characterization by Infrared Spectroscopy and Ultrasonic Velocimetry

Schultz

Levin

2008

Biophysical Journal

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We demonstrate the use of vibrational infrared spectroscopy applied to characterize lipid microdomain sizes derived from a model raft-like system consisting of nonhydroxy galactocerebroside, cholesterol, and dipalmitoylphosphatidylcholine components. The resulting spectroscopic correlation field components of the lipid acyl chain CH 2 methylene deformation modes, observed when lipid multilamellar assemblies are rapidly frozen from the liquid crystalline state to the gel phase, indicate the existence of lipid microdomains on a scale of several nanometers. The addition of cholesterol disrupts the glycosphingolipid selectively but perturbs the di-saturated chain phospholipid matrix. Complementary acoustic velocimetry measurements indicate that the microdomain formation decreases the total volume adiabatic compressibilities of the multilamellar vesicle assemblies. The addition of cholesterol, however, disrupts the galactocerebroside domains, resulting in a slight increase in the lipid assemblies' total adiabatic compressibility. The combination of these two physical approaches offers new insight into microdomain formation and their properties in model bilayer systems.

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“…Another method that has been employed to determine the phase transition is Fourier Transform Infrared Spectroscopy (FTIR) [21][22][23] . Several peaks assigned to the vibrational modes of different groups of the phospholipid molecule can be followed at different temperatures which provides a tool to measure nanoscale domain size and chain order parameters 15,22 .…”

Section: Introductionmentioning

confidence: 99%

“…Several peaks assigned to the vibrational modes of different groups of the phospholipid molecule can be followed at different temperatures which provides a tool to measure nanoscale domain size and chain order parameters 15,22 .…”

Section: Introductionmentioning

confidence: 99%

Microthermodynamic Interpretation of Fluid States from FTIR Measurements in Lipid Membranes: A Monte Carlo Study

et al. 2014

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Fourier transform infrared spectroscopy (FTIR) is usually employed to obtain transition temperatures of lipids and lipid mixtures and the effect on it of several effectors, such as cholesterol. However, no interpretation of the molecular information provided by the frequency shift to higher values observed at Tc is available. In this article, we demonstrate that data obtained by means of FTIR measurements contain information about the microscopic thermodynamics of the lipid-phase transition. By means of Monte Carlo simulation, we have been able to show that the frequency shift from low to high values can be taken as a two-state transition of molecular constituents in a lattice rearrangement. According to the model, at temperatures below Tc all of the groups are defined in the lowest-energy state defined by the lowest frequency value and therefore they are all connected in a gel lattice. Above Tc, some groups may reach different energy states depending on the restrictions imposed on the groups. Ideally, when all of the groups are able to reach the highest frequency, a fully "fluid" state is reached, which is a disordered state. If we take this hypothetical state as a reference, it is possible to show that the higher states become less accessible. The model is suitable for describing the effect of cholesterol, which is able to dump the phase transition and is congruent with previous data denoting that in the so-called fluid phase the first four to five methylene groups remain in the gel state even above Tc. The frequency value attained above Tc depends on the nature of the lipid acyl chain.

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IR spectroscopic determination of gel state miscibility in long-chain phosphatidylcholine mixtures

Cited by 64 publications

References 23 publications

The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs

The interfacial structure of phospholipid bilayers: differential scanning calorimetry and Fourier transform infrared spectroscopic studies of 1,2-dipalmitoyl-sn-glycero-3-phosphorylcholine and its dialkyl and acyl-alkyl analogs

Lipid Microdomain Formation: Characterization by Infrared Spectroscopy and Ultrasonic Velocimetry

Microthermodynamic Interpretation of Fluid States from FTIR Measurements in Lipid Membranes: A Monte Carlo Study

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