A statistical mechanical treatment of fatty acyl chain order in phospholipid bilayers and correlation with experimental data. A. Theory

Meraldi, Jean‐Paul; Schlitter, Jürgen

doi:10.1016/0005-2736(81)90189-9

Cited by 41 publications

(20 citation statements)

References 31 publications

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“…We believe that these local variations reflect local geometry of the acyl chains and are not of primary interest in characterizing the anisotropic nature of bilayer order. Several theories (Marcelja, 1974;Jaihnig, 1979;Dill and Flory, 1980;Meraldi and Schlitter, 1981) have reproduced the order distribution along the chain. Two of them (Jahnig, 1979;Dill and Flory, 1980) give smoothed profiles.…”

Section: Discussionmentioning

confidence: 97%

“…Two of them (Jahnig, 1979;Dill and Flory, 1980) give smoothed profiles. To simulate accurately the experimental data, the statistical mechanical treatment (Meraldi and Schlitter, 1981) had to introduce several free parameters to express the geometrical properties of chain conformations. However, in the Meraldi and Schlitter (1981) model as well as in the others, the overall shape of the order profile is reproduced taking in account the main factors responsible for the organization of the lipids such as trans-gauche isomerization, lateral pressure, van der Waals interactions, and steric hindrance.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Smoothed orientational order profile of lipid bilayers by 2H-nuclear magnetic resonance

Lafleur

Fine

Sternin

et al. 1989

Biophysical Journal

224

247

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A new method has been developed to determine the complete orientational order profile of lipid bilayers using 2H-NMR. The profile is obtained from a single powder spectrum of a lipid which has a saturated chain fully deuteriated. The smoothed order profile is determined directly from the normalized dePaked spectrum assuming a monotonic decrease of the order along the acyl chain. The oscillatory variations of the order at the beginning of the chain are not described by this method. However the smoothed order profile reveals in a straightforward way the crucial features of the anisotropic order of the bilayer.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Smoothed orientational order profile of lipid bilayers by 2H-nuclear magnetic resonance

Lafleur

Fine

Sternin

et al. 1989

Biophysical Journal

224

247

View full text Add to dashboard Cite

show abstract

“…A variety of different parameters have already been suggested. Using the van der Waals model, Meraldi and Schlitter (1981) have used the lateral pressure as the crucial parameter to simulate the order distribution. The absolute value of order parameters as well as the plateau length are both affected by a change of lateral pressure and their calculations predict that the plateau should be longer for more ordered chains.…”

Section: Discussionmentioning

confidence: 99%

Modulation of the orientational order profile of the lipid acyl chain in the L? phase

1990

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The orientational order profile along the lipid acyl chain has been characterized under several different conditions of polar headgroup composition, temperature, and cholesterol content. Despite the different nature of these factors, the variation of the order is governed by two common trends. First, the relative change of order induced by the variation of these factors is always more pronounced towards the end of the chain than for the methylene groups near the interface. Second, there is, to a first approximation, a distinct correlation between the magnitude of the order parameters and the shape of the order profile. For example when the chain is highly ordered, the relative width of the order distribution is narrow indicating that the plateau region is longer. These conclusions suggest that the orientational order profile depends on only a small number of parameters and demonstrate clearly that the correlation length for changes in orientational order is much greater than one C-C bond length. Our results also show that the reduced temperature is not related in simple terms to orientational order and probably has little theoretical significance. The orientational order profiles of POPC and POPE bilayers are significantly different even when expressed in terms of reduced temperature. The behavior of POPC/cholesterol systems also indicates that the orientational order of the lipid chain and the gel-to-liquid crystalline phase transition temperature are not related in a straightforward manner.

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“…From the lateral pressure profile calculated above we obtain yhc = 27.6 dyn/cm, a value that is very close to the surface tension of * 27.3 dyn/cm in the hydrocarbon chain region in a dipalmitoyl phosphatidylcholine lipid bilayer used by Gruen (1980) in a statistical mechanical calculation to fit experimental order parameters (Seelig and Seelig, 1974). In the following two sections, the effects of excluded vol- 5 10 15 20 ume interactions, as expressed by the reversible work, on the orientational distribution and relative partition coefficient of model lipid bilayer versus solute in an interphase are examined as the anisotropy of the mean attractive interaction energy plays a somewhat secondary role (Meraldi and Schlitter, 1981;Warner, 1980). physical intuition that there is a much higher probability for a chain segment to be located adjacent to a neighboring chain segment belonging to a different chain molecule in the (x, y) domain than along the z direction in the highly ordered chain region.…”

Section: (6)mentioning

confidence: 99%

Molecular distributions in interphases: statistical mechanical theory combined with molecular dynamics simulation of a model lipid bilayer

Xiang

Anderson

1994

Biophysical Journal

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A mean-field statistical mechanical theory has been developed to describe molecular distributions in interphases. The excluded volume interaction has been modeled in terms of a reversible work that is required to create a cavity of the solute size against a pressure tensor exerted by the surrounding interphase molecules. The free energy change associated with this compression process includes the configuration entropy as well as the change in conformational energy of the surrounding chain molecules. The lateral pressure profile in a model lipid bilayer (30.5 A2/chain molecule) has been calculated as a function of depth in the bilayer interior by molecular dynamics simulation. The lateral pressure has a plateau value of 309 +/- 48 bar in the highly ordered region and decreases abruptly in the center of the bilayer. Model calculations have shown that for solute molecules with ellipsoidal symmetry, the orientational order increases with the ratio of the long to short molecular axes at a given solute volume and increases with solute volume at a given axial ratio, in accordance with recent experimental data. Increased lateral pressure (p perpendicular) results in higher local order and exclusion of solute from the interphase, in parallel with the effect of surface density on the partitioning and local order. The logarithm of the interphase/water partition coefficient for spherical solutes decreases linearly with solute volume. This is also an excellent approximation for elongated solutes because of the relatively weak dependence of solute partitioning on molecular shape. The slope is equal to (2p perpendicular - p parallel)/3KBT, where p parallel is the normal pressure component, and different from that predicted by the mean-field lattice theory. Finally, the lattice theory has been extended herein to incorporate an additional constraint on chain packing in the interphase and to account for the effect of solute size on partitioning.

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A statistical mechanical treatment of fatty acyl chain order in phospholipid bilayers and correlation with experimental data. A. Theory

Cited by 41 publications

References 31 publications

Smoothed orientational order profile of lipid bilayers by 2H-nuclear magnetic resonance

Smoothed orientational order profile of lipid bilayers by 2H-nuclear magnetic resonance

Modulation of the orientational order profile of the lipid acyl chain in the L? phase

Molecular distributions in interphases: statistical mechanical theory combined with molecular dynamics simulation of a model lipid bilayer

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