Biomaterial Database

Asymmetric and symmetric membrane reconstitution by detergent elimination. Studies with Semliki-Forest-virus spike glycoprotein and penicillinase from the membrane of Bacillus licheniformis. 1981

A Helenius, and M Sarvas, and K Simons

The dissociation and reconstitution of the Semliki Forest virus membrane using the nonionic detergent octyl beta-D-glucoside was studied by sucrose density gradient centrifugation. The dissociation occurred in three stages: lysis at a free equilibrium octyl glucoside concentration of 14--18 mM, solubilization at 18--20 mM, and delipidation of the spike glycoproteins at the critical micellar concentration (22 mM) or higher. After solubilization the spike glycoproteins were present as soluble complexes with sedimentation coefficients of 19 S and 6 S. The 6-S form probably corresponded to a glycoprotein monomer complexed to detergent and the 19-S form consisted of oligomeric detergent-protein complexes. The two forms were in slow equilibrium with each other. When the soluble spike protein complexes and egg lecithin solubilized with octyl glucoside were mixed and the octyl glucoside concentration lowered either by dialysis or by dilution, reconstitution occurred. Three types of products were obtained: vesicles with 30% of the spike protein facing inwards and 70% facing outwards, vesicles with virtually all (95%) of the spike proteins pointing outwards, and small protein-rich soluble aggregates [Helenius et al. (1977) J. Cell Biol. 75, 866]. It was demonstrated that during reconstitution the symmetric vesicles were formed at 19 mM free equilibrium octyl glucoside by the association of the 6-S protein complexes with the phospholipids, and the asymmetric vesicles were formed at 10--16 mM octyl glucoside when the 19-S complexes associated with the lipids. Asymmetric membrane vesicles were also obtained when membrane penicillinase from Bacillus licheniformis was reconstituted with egg lecithin using octyl glucoside. It could be shown that the penicillinase was oligomeric at the octyl glycoside concentration where the reconstitution occurred. The results demonstrate that different mechanisms of reconstitution give rise to the symmetric and the asymmetric vesicles. The critical factor in determining the mechanism is the state of aggregation of the proteins at the octyl glucoside concentration where membranes begin to form from the solubilized lipids.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D010405	Penicillinase	A beta-lactamase preferentially cleaving penicillins. (Dorland, 28th ed) EC 3.5.2.-.	beta-Lactamase I,AER-I beta-Lactamase,Benzylpenicillinase,Carbenicillinase,Exopenicillinase,beta Lactamase III,beta Lactamase RP4,gamma-Penicillinase,AER I beta Lactamase,Lactamase RP4, beta,beta Lactamase I,beta-Lactamase, AER-I,gamma Penicillinase
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
D003902	Detergents	Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.	Cleansing Agents,Detergent Pods,Laundry Detergent Pods,Laundry Pods,Syndet,Synthetic Detergent,Agent, Cleansing,Agents, Cleansing,Cleansing Agent,Detergent,Detergent Pod,Detergent Pod, Laundry,Detergent Pods, Laundry,Detergent, Synthetic,Detergents, Synthetic,Laundry Detergent Pod,Laundry Pod,Pod, Detergent,Pod, Laundry,Pod, Laundry Detergent,Pods, Detergent,Pods, Laundry,Pods, Laundry Detergent,Synthetic Detergents
D006023	Glycoproteins	Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins.	C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated
D001407	Bacillus	A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.	Bacillus bacterium
D001618	beta-Lactamases	Enzymes found in many bacteria which catalyze the hydrolysis of the amide bond in the beta-lactam ring. Well known antibiotics destroyed by these enzymes are penicillins and cephalosporins.	beta-Lactamase,beta Lactamase,beta Lactamases
D012672	Semliki forest virus	A species of ALPHAVIRUS isolated in central, eastern, and southern Africa.
D014764	Viral Proteins	Proteins found in any species of virus.	Gene Products, Viral,Viral Gene Products,Viral Gene Proteins,Viral Protein,Protein, Viral,Proteins, Viral
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular