Lipid interactions in membranes

Hunte, C., Specific protein-lipid interactions in membrane proteins, Biochem Soc Trans 33 (2005) 938-942. 

Pohorille, A., New, M. H., Schweighofer, K. and Wilson, M. A. (1999). Insights from computer simulations into the interactions of small molecules with lipid bilayers. In Membrane Permeability, Vol. 48 100 Years Since Ernest Overton, eds. Deamer, D. W., Kleinzeller, A. and Fambrough, D. M., Academic Press, San Diego pp. 50-76. 

Protein-lipid interaction in retinal-rod outer disc membranes in sonicated vesicles is suggested from comparison of the T1 data of these vesicles with those of extracted liposome preparations from the same source (Brown et al., 1976). Chloroplast thylakoids form micellar structures in chloroform and bilayer structures in water. It was shown by 13C relaxation (Johns et al., 1977) that T1 data are sensitive to this change in secondary structure. As in the... 

Even though our understanding of the possible types of lipid-protein interactions in membranes has developed only recently, it was evident to early investigators that neutral solvents per se were the most effective for isolation purposes. Perhaps the most widely used solvent extraction procedure for many years was that employing a mixture of ethanol-diethyl ether (usually 1 3, v/v). This technique involved extraction of a tissue with this solvent combination for several hours at 55-60°C (Bloor, 1928). However, as more refined techniques were developed for the detection and assay of lipids, it became evident that this solvent (and condition) could have a deleterious... 

In Fig. 3, a model is shown for the interaction between protein molecules and a nonpolar support. Unlike the lipid present in membranes and lipoprotein particles, the reversed-phase Qg group is anchored to the polar silica surface. It is not possible, therefore, for the C, chains to completely avoid the polar silica surface and the polar mobile phase. In 1972, Scott and Kucera (55) provided evidence that the nonpolar regions of the organic modifier are oriented in a manner that shields the C, phase from both polar phases. In Fig. 3, the modifier is shown as methanol, but a similar result would be expected for other solvents such as CHgCN, (CH3)jjCHOH, and CHgCHgCHgOH. 

Mouritsen, O. G. and Bloom, M., Models of lipid-protein interactions in membranes. Annual Review of Biophysics and Biomolecular Structure 22 145-171, 1993. 

AndreollTE. On the anatomy of amphotericin B-cholesterol pores in lipid bilayer membranes. Kidney Int 1973 4 337-45. DeKruijiff B, Demel RA. Polyene antibiotic-sterol interactions in membranes of Acholeplesma laidlawii cellsand lecithin liposomes. III. Molecular structure of the polyene antibiotic-cholesterol complexes. Biochem Biophys Acta 1974 339 57-70. HoIzRW.Theeffectsofthe polyene antibiotics nystatin and amphotericin Bon thin lipid membranes. Ann N Y Acad Sell 974 235 469-79. 

Figure 18.1 Models for different modes of peptide-lipid interaction of membrane-active peptides. The peptide remains unstructured in solution and acquires an amphipathic structure in the presence of a membrane. The hydrophobic face of the amphipathic peptide binds to the membrane, as represented by the grayscale. At low concentration, the peptide lies on the surface. At higher peptide concentrations the membrane becomes disrupted, either by the formation of transmembrane pores or by destabilization via the "carpet mechanism." In the "barrel-stave pore" the pore consists of peptides alone, whereas in the "toroidal wormhole pore" negatively charged lipids also line the pore, counteracting the electrostatic repulsion between the positively charged peptides. The peptide may also act as a detergent and break up the membrane to form small aggregates. Peptides can also induce inverted micelle structures in the membrane.

W. B. Huttner and A. Schmidt, Lipids, lipid modification and lipid-protein interaction in membrane budding and fission-insights from the roles of endophilin Al and synaptophysin in synaptic vesicle endocytosis, Curr. Opin. Neurobiol.,... 

Further interaction of reduced paraquat with hydrogen peroxide could yield the more reactive hydroxyl free radical (39) which could initiate lipid peroxidation in membrane fatty acids. 

Hilty et alP have used spin labels to study protein-lipid interactions in mixed micelles containing dihexanoylphosphatidylcholine and the E. coli outer-membrane protein X (OmpX). As paramagnetic relaxation probes, they used several different nitroxide spin labels attached to the lipid as well as Gd-DOTA, which remains in the aqueous phase. Spectral perturbations were monitored in TROSY and ID H NMR spectra. 

How membrane fluidity influences the functional stability of the membrane proteins is not known. Fluidity determined by spin label motion is at best a comparative measure. The increase in motion is indicative of less resistance by the acyl chains of the host lipids for the spin label to tumble and as such measures the increase in vibrational frequency of the acyl chains. A hypothesis has been advanced to explain the increase in chlorophyll fluorescence in terms of the differential effect of temperature on the force of the hydrophilic and hydrophobic interactions in membranes. The direct correlation between the temperature of the functional change and the fluidity at this temperature suggests that fluidity is a good indicator of the critical point in the balance of these interactions. 

Mouritsen OG, Bloom M (1984) Mattress model of lipid-protein interactions in membranes. Biophys J 36 141-153... 

Fattal DR, Btat-Shaul A (1995) Lipid chain packing and lipid-protein interaction in membranes. Phys A 220 192-216... 

The modification of the regulatory activity of the membranes on its bound enzymes has the particularity of being highly specific for each particular enz3nne since it depends on the alteration of the lipid environment surrounding the enzyme. The modification of the lipid environment through feeding conditions led to some particular protein-lipid interaction in each membrane for each... 

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