Biomaterial Database

Synergistic effects of Ca2+ and wheat germ agglutinin on the lamellar-hexagonal (HII) phase transition of glycophorin-containing egg-phosphatidylethanolamine membranes. 1991

R Tampé, and H J Galla

Institute of Biochemistry, Technical University Darmstadt, Federal Republic of Germany.

Glycophorin has been reconstituted into egg phosphatidylethanolamine (egg-PtdEtn) membranes. Stable vesicles were obtained at a molar ratio of 8 x 10(-4) of inserted protein/lipid. This macroscopic change from lipid aggregates to lipid vesicles was followed by density gradient centrifugation. Vesicles formed in the presence of protein enclose the dye calcein and are stable with time and temperature. Membrane aggregation does not occur, as was demonstrated by energy-transfer experiments. The phase transition from the fluid lamellar L alpha phase to the inverted hexagonal HII phase observed at 29 degrees C in pure egg-PtdEtn membranes is suppressed and finally disappears in the presence of glycophorin. The transition enthalpy decreases linearly from delta H = 4 kJ/mol in pure lipids to zero at a protein/lipid molar ratio of 1:1000. Ca2+ ions and wheat germ lectin act synergistically on the phase behavior of vesicles containing glycophorin and phosphatidylethanolamine. Differential scanning calorimetry scans show that the lamellar-to-hexagonal phase transition is reinduced. The membranes aggregate and exchange lipid as could be demonstrated by energy transfer experiments. The dye calcein is released but only if the temperature exceeds the lamellar-to-hexagonal phase transition temperature of the pure egg-PtdEtn.

UI	MeSH Term	Description	Entries
D010714	Phosphatidylethanolamines	Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.	Cephalin,Cephalins,Ethanolamine Phosphoglyceride,Ethanolamine Phosphoglycerides,Ethanolamineglycerophospholipids,Phosphoglyceride, Ethanolamine,Phosphoglycerides, Ethanolamine
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002152	Calorimetry, Differential Scanning	Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.	Differential Thermal Analysis, Calorimetric,Calorimetric Differential Thermal Analysis,Differential Scanning Calorimetry,Scanning Calorimetry, Differential
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
D004357	Drug Synergism	The action of a drug in promoting or enhancing the effectiveness of another drug.	Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D004531	Eggs	Animal reproductive bodies, or the contents thereof, used as food. The concept is differentiated from OVUM, the anatomic or physiologic entity.
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D005454	Fluorescence Polarization	Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.	Anisotropy, Fluorescence,Fluorescence Anisotropy,Polarization, Fluorescence,Anisotropies, Fluorescence,Fluorescence Anisotropies,Fluorescence Polarizations,Polarizations, Fluorescence
D006021	Glycophorins	The major sialoglycoprotein of human erythrocyte membranes. It consists of at least two sialoglycopeptides and is composed of 60% carbohydrate including sialic acid and 40% protein. It is involved in a number of different biological activities including the binding of MN blood groups, influenza viruses, kidney bean phytohemagglutinin, and wheat germ agglutinin.	Erythrocyte Sialoglycoproteins,Glycoconnectin,Glycoconnectins,Glycophorin,Glycophorin D,MN Sialoglycoprotein,Red Blood Cell Membrane Sialoglycoprotein,Glycophorin A,Glycophorin A(M),Glycophorin B,Glycophorin C,Glycophorin E,Glycophorin HA,Ss Erythrocyte Membrane Sialoglycoproteins,Ss Sialoglycoprotein,beta-Sialoglycoprotein,Sialoglycoprotein, MN,Sialoglycoprotein, Ss,Sialoglycoproteins, Erythrocyte,beta Sialoglycoprotein
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures