Biomaterial Database

Incorporation of photosensitive fatty acids into phospholipids of Escherichia coli and irradiation-dependent cross-linking of phospholipids to membrane proteins. 1981

S C Quay, and R Radhakrishnan, and H G Khorana

In an approach to the study of phospholipid-protein interactions in biological membranes, the photoactivable fatty acids, omega-(m-azidophenoxy)-undecanoic acid (I) and omega-(m-diazirinophenoxy)-hexadecanoic acid (II), were incorporated biosynthetically into the phospholipids of the Escherichia coli fatty acid auxotroph, strain K1060-B5. The extent of incorporation of the two fatty acids was 43% and 21%, respectively, of the total fatty acid content of the phospholipids. Membrane vesicles prepared from cells grown on the fatty acid supplements and [32P]H3PO4 were irradiated at suitable wavelengths to generate the reactive nitrene or carbene intermediates. Subsequent analysis of solubilized membrane proteins by two-dimensional isoelectric focusing-polyacrylamide gel electrophoresis indicated cross-linking between radioactive phospholipids and an number of proteins. A corresponding experiment with cells grown on oleic acid showed only trace amounts of covalently cross-linked phospholipid-protein adducts. While the extent of cross-linking in vesicles from cells grown on I was only 3 times the background level observed for oleic acid-grown cells, cells grown on II showed 30 times this amount. The present results, together with the previously observed nonreactivity of the nitrene generated from I to undergo C-H insertion, show that the use of carbene precursors such as II is promising for chemical analysis of specific phospholipid-protein interactions in bacterial membranes under biologically meaningful conditions.

UI	MeSH Term	Description	Entries
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010169	Palmitic Acids	A group of 16-carbon fatty acids that contain no double bonds.	Acids, Palmitic
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D010782	Photolysis	Chemical bond cleavage reactions resulting from absorption of radiant energy.	Photodegradation
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D003432	Cross-Linking Reagents	Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.	Bifunctional Reagent,Bifunctional Reagents,Cross Linking Reagent,Crosslinking Reagent,Cross Linking Reagents,Crosslinking Reagents,Linking Reagent, Cross,Linking Reagents, Cross,Reagent, Bifunctional,Reagent, Cross Linking,Reagent, Crosslinking,Reagents, Bifunctional,Reagents, Cross Linking,Reagents, Cross-Linking,Reagents, Crosslinking
D004591	Electrophoresis, Polyacrylamide Gel	Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.	Polyacrylamide Gel Electrophoresis,SDS-PAGE,Sodium Dodecyl Sulfate-PAGE,Gel Electrophoresis, Polyacrylamide,SDS PAGE,Sodium Dodecyl Sulfate PAGE,Sodium Dodecyl Sulfate-PAGEs