Protein with lipid

Scheme 1. Posttranslational modification of Ras protein with lipid groups (FPP Farnesyl-pyrophosphate, PalCoA Palmitoyl CoA)...

Lian, T., T. Bui, and R.J. Ho, Formulation of HFV-envelope protein with lipid vesicles expressing ganglioside GMl associated to cholera toxin B enhances mucosal immune responses. Vaccine, 1999. 18(7-8) 604-11. 

Vandeheuvel s model is likely with polar lipids aligned as surfactants at the water interface. The reported proteolipids and glycoproteolipids may be ER protein with lipids incorporated into the hydrophobic portion that contacts the hydrocarbon chains of other polar lipids. Lipids may be combined with the protein during lysis. 

TiTuch of our understanding of the phase behavior of insoluble - monolayers of lipids at the air-water interface is derived from Adam s studies of fatty acid monolayers (I). It is now clear that the phase behavior of phospholipid monolayers (2) parallels that of the fatty acids we make use of these structure variations in our study of the interactions of phosphatidylcholine (lecithin) monolayers with proteins. Because of the biological significance of the interfacial behavior of lipids and proteins, there is a long history of studies on such systems. When Adam was studying lipid monolayers, other noted contemporary surface chemists were studying protein monolayers (3) and the interactions of proteins with lipid monolayers (4). The latter interaction has been studied by many so-called 4 penetration experiments where the protein is injected into the substrate below insoluble lipid monolayers that are spread on the... 

Fig. 12 On-surface reconstitution of immobilized membrane proteins with lipid bUayers by injection of mixed micelles and rapid detergent elution...

Swertfeger DK, Hui DY. Apolipoprotein E a cholesterol transport protein with lipid transport-independent cell signaling properties. Front Biosci 2001 6 D526-D535. 

A biological membranes system is typically formed by the combination of lipids and proteins. In eukaryotic cells, the plasma membrane, also referred to as the cell membrane, is a protective barrier which regulates what enters and leaves the cell. The endomembrane system is composed of different kinds of membranes which divide the cell into structural and functional compartments within a eukaryotic cell, such as the endoplasmic reticulum, Golgi apparatus, mitochondria, endosome and lysosome. Covalent modification of proteins with lipid anchors (protein lipidation) facilitates association of the lipidated proteins with particular membranes in eukaryotic cells. Protein lipidation is one of the most important protein post-translational modifications (PTMs). Studying lipidated protein function in vitro or in vivo is of vital importance in biological research. 

In addition to pure proteins, there are still several classes of what are known as conjugated proteins, that is, compounds of proteins with non-o-amino acids, i.e., with what are called prosthetic groups. Chromoproteins are such compounds of proteins with metals. Glycoproteins contain less than 4%, but mucoproteins more than 4%, polysaccharides. Compounds of proteins with lipids are called lipoproteins, those with nucleic acids nucleoproteins, and those with flavine derivatives flavoproteins. Hemoproteins are compounds of proteins and iron porphyrines. 

It seems to be a general rule that, as far as possible, hydrophobic side chains are buried in the interior of protein molecules leaving the polar and charged side chains on the surface. Proteins are, in the main, close packed structures and the hydrophobic amino acids take up space without interacting with water so that they are useful in providing bulk and shape to the interior of the molecule. However, there are usually more non-polar side chains than can be accommodated in the interior and some are exposed on the surface. If these are concentrated in a particular area to give a hydrophobic patch they may be important in the development of quaternary structure and also in the association of proteins with lipids as in membrane structures. 

IV Complex bacteriocins protein with lipid and/or carbohydrate Lactobacillus, Leuconostoc, Pediococcus... 

Fantini J. Interaction of proteins with lipid rafts through glycolipid-binding domains biochemical background and potential therapeutic applications. CurrMed Chem. 2007 14(27) 2911-2917. 

Experimental data offered as evidence for hydrophobic bonding of lipids to protein by Green and Tzagaloff (1966) can be readily given interpretations which exclude hydrophobic bond involvement of the protein with lipid chains. For example, (1) the stronger binding to mitochondrion structural protein of lipids with longer acyl chains... 

The situation is even worse for membrane lipids. Not a single, naturally occurring phospholipid with unsaturated hydrocarbon chains has yet been crystallized. However, nearly 40 crystal structures of closely related synthetic glycerolipids with saturated hydrocarbon chains have been solved by X-ray. On the structural level, little is known about the interactions of proteins with lipid bilayer environments. Detergent molecules have been detected in some of the X-ray structures, and a small number of studies discuss lipids bound to proteins. An example is cytochrome C oxidase crystals, where the lipids were found to be arranged in a bilayer structure. 

Newton, A.C., Interaction of proteins with lipid headgroups lessons from protein kinase C, Annu. Rev. Biophys. Biomol. Struct., 22, 1, 1993. 

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