Incorporation into lipid vesicle

Purified membrane proteins or enzymes can be incorporated into these vesicles in order to assess what factors (eg, specific lipids or ancillary proteins) the proteins require to reconstitute their function. Investigations of purified proteins, eg, the Ca " ATPase of the sarcoplasmic reticulum, have in certain cases suggested that only a single protein and a single lipid are required to reconstitute an ion pump. 

We assume that the affinities of these specific IgG molecules for spin-labeled lipid haptens such as (V), (IX), or (X) are of the same order of magnitude. Figure 10 illustrates the effect of antibody binding on the paramagnetic resonance spectra of (X) incorporated into lipid membrane vesicles. 

Complex II consists of four polypeptide subunits (70,000, 27,000, 13,500, and 7,000 daltons). The two larger subunits are components of succinate dehydrogenase and this enzyme or the entire complex II was directly incorporated into phospholipid vesicles at the high protein lipid ratio of 1 2 (w/w). The phospholipid (egg yolk lecithin) contained a small amount of lipid (d) (Table 6.2 I molecule in 1000) or lipid (e) (Table 6.2 1 in 400). After irradiation the labeling pattern was analyzed directly by SDS-polyacrylamide gel electrophoresis. Presumably the lipids that did not become attached to polypeptides ran at the dye front, although this was not demonstrated. 

Jay, D. G. and Gilbert, W. (1987). Basic protein enhances the incorporation of DNA into lipid vesicles model for the formation of primordial cells. Proceedings of the National Academy of Sciences. USA, 84,1978-80. 

Incorporation of Alamethicin into Lipid Vesicle Membranes and Generation of Donnan Potential Gradient across the Membrane. Alamethicin from Tricho-derma viride was purchased from Sigma and used without further purification. 

Use of encapsulated labeled precursors in lipid vesicles enabled the Hawaiian group to conduct the biosynthetic studies - with the exception of workup of the sponge - entirely in the field. Incorporation of doubly labeled [13C, 15N]cyanide into a Ciocalypta sp. and an Acanthella sp. produced labeled 9-isocyanoneopupukeanane (77) and kalihinol-F (112) respectively [71]. Detection of incorporation was followed by 13C NMR experiments. 

Fig. 9 Surface modification of cells with ssDNA-PEG-lipid. (a) Real-time monitoring of PEG-lipid incorporation into a supported lipid membrane by SPR. (r) A suspension of small unilamellar vesicles (SUV) of egg yolk lecithin (70 pg/mL) was applied to a CH3-SAM surface. A PEG-lipid solution (100 pg/mL) was then applied, (ii) Three types of PEG-lipids were compared PEG-DMPE (C14), PEG-DPPE (C16), and PEG-DSPE (C18) with acyl chains of 14, 16, and 18 carbons, respectively, (b) Confocal laser scanning microscopic image of an CCRF-CEM cell displays immobilized FITC-oligo(dA)2o hybridized to membrane-incorporated oligo(dT)20-PEG-lipid. (c) SPR sensorigrams of interaction between oligo(dA)2o-urokinase and the oligo (dT)2o-PEG-lipid incorporated into the cell surface, (i) BSA solution was applied to block nonspecific sites on the oligo(dT)20-incorporated substrate, (ii) Oligo(dA)20-urokinase (solid line) or oligo(dT)20-urokinase (dotted line) was applied...

Vesicular proteins and lipids that are destined for the plasma membrane leave the TGN sorting station continuously. Incorporation into the plasma membrane is typically targeted to a particular membrane domain (dendrite, axon, presynaptic, postsynaptic membrane, etc.) but may or may not be triggered by extracellular stimuli. Exocytosis is the eukaryotic cellular process defined as the fusion of the vesicular membrane with the plasma membrane, leading to continuity between the intravesicular space and the extracellular space. Exocytosis carries out two main functions it provides membrane proteins and lipids from the vesicle membrane to the plasma membrane and releases the soluble contents of the lumen (proteins, peptides, etc.) to the extracellular milieu. Historically, exocytosis has been subdivided into constitutive and regulated (Fig. 9-6), where release of classical neurotransmitters at the synaptic terminal is a special case of regulated secretion [54]. 

Figure 5. Lipid effects on the oxygen-evolving activity of PS n incorporated into vesicle at 40°C.

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