Biomaterial Database

Isolation and chemical composition of the cytoplasmic membrane of the archaebacterium Methanospirillum hungatei. 1983

G D Sprott, and K M Shaw, and K F Jarrell

The cytoplasmic membrane of Methanospirillum hungatei was isolated from osmotic lysates of spheroplasts, with yields of 7-8% of the cell dry weight. Cytoplasmic contamination was negligible, as judged by the removal of soluble enzymes. The cytoplasmic membrane consists of lipid (35-37%), primarily as a biphytanyldiglycerol tetraether glycolipid; protein (45-50%); and carbohydrate (10-12%). Ultra-thin sections showed that the trilaminar membrane formed vesicles with a maximum diameter of 0.4 microns. Protrusions of membrane projecting from the vesicles were seen often in negatively stained preparations. Fractionation of M. hungatei cells grown in the presence of [14C]mevalonic acid revealed that 90% of the phytanyl lipids were present in the cytoplasmic membrane band, with two minor bands accounting for the remainder of the label. Approximately 50% of the galactose, glucose, and mannose present in the cytoplasmic membrane was found in lipid extracts, while the remainder of these sugars and 98% of the rhamnose were present as nonlipid sugars. The cell sheath, isolated with a yield of 13% of the cell dry weight, contained the same sugars as the cytoplasmic membrane, but in very different proportions. Amino acid analysis of the membrane proteins showed that hydrophobic amino acid residues made up 37% of the total, neutral amino acids, 39%, basic, 8%, acidic, 16%, and that half-cysteine was present. Sodium dodecyl sulfate-polyacrylamide gel patterns of solubilized cytoplasmic membrane proteins revealed major bands at 195, 74.5, 44, 32, and 30 KDa. Significant amounts of nickel co-isolated with the cytoplasmic membrane, accounting for 0.16% of the membrane dry weight.

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
D008798	Mevalonic Acid	A dihydroxy monocarboxylic acid and precursor in the biosynthetic pathway known as the mevalonate pathway, which produces terpenes and steroids that are vital for diverse cellular functions.	Mevalonate,Acid, Mevalonic
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
D009532	Nickel	A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.
D002241	Carbohydrates	A class of organic compounds composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n. The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES.	Carbohydrate
D002250	Carbon Radioisotopes	Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.	Radioisotopes, Carbon
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
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
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density