Fluidity Parameters of Lipid Regions Determined by Fluorescence Polarization

Cholesterol and the cell membrane.

The motivation for this review arises from the conviction that, as a result of the mass of experimental data and observations collected in recent years, the study of the physical properties of membranes is now entering a new stage of development. More and more, experiments are being designed to answer specific, detailed questions about membranes which will lead to a quantitative understanding of the way in which the physical properties of membranes are related to and influence their biological function.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033583500003735

Physical properties of the fluid lipid-bilayer component of cell membranes: a perspective.

Lipid intermolecular hydrogen bonding: influence on structural organization and membrane function.

Chemical stability of liposomes: implications for their physical stability

Based on the structural properties of phospholipid and cholesterol molecules, and making use of the known structural and motional effects of cholesterol and its analogs on phospholipid bilayers, a model for the cholesterol-phosphatidylcholine complex is proposed. In this model, the 3β-hydroxyl group of cholesterol is assumed to engage in hydrogen bonding with the carbonyl oxygen of the fatty acyl groups in phospholipids. Some specific configurations of the saturated and unsaturated fatty acyl chains of the phospholipid are suggested to participate in van der Waals attractive interactions with the α and β surface of the steroid nucleus.

A structural model for the cholesterol-phosphatidylcholine complexes in bilayer membranes.

Fully hydrated lysophospholipids in both the gel and the liquid crystalline states have been shown to exhibit negative phosphorus chemical shift anisotropies (Δσ) by31P nuclear magnetic resonance (NMR). The magnitude of Δσ for monoacyl lysophospholipids is found to be smaller than that of the corresponding diacyl phosphospholipids in bilayers by about a factor of two. We present evidence to suggest that the reduction in Δσ can be attributed primarily to an additional motional averaging of the lysophospholipid headgroup, and the additional motion can best be explained by rapid rotational motions of the headgroup about the C(1)-C(2) glycerol bond.

A nuclear magnetic resonance spectroscopic investigation of the headgroup motions of lysophospholipids in bilayers

Recently, several studies have shown that the rate of lateral diffusion of liquid-crystalline phospholipids in various phospholipid/water lamellar systems depends markedly on the hydration over the water content of 15–40 w/w%. In this paper, we calculated the change in lipid lateral diffusion as a function of water content according to the theory of Brownian motion in thin sheets developed by Saffman and Delbruck. These calculations, based on experimental data of lipid dimensions and bulk water diffusion coefficients obtained for the egg phosphatidylcholine/water system at various water contents, clearly indicate that the dependence of lipid lateral diffusion on the hydration can be attributed primarily to the change in bulk water mobility in the multilamellar phospholipid/water system.

Ching-Hsien Huang

Papers

A structural model for the cholesterol-phosphatidylcholine complexes in bilayer membranes.

A nuclear magnetic resonance spectroscopic investigation of the headgroup motions of lysophospholipids in bilayers

Effect of water mobility on lateral diffusion of phospholipids in liposomes