Monopolar-bipolar lipid interactions in model membrane systems.

Z Mirghani; D Bertoia; A Gliozzi; M De Rosa; A Gambacorta

doi:10.1016/0009-3084(90)90069-4

Home/Archive/PubMed

PubMed · 2090362

Monopolar-bipolar lipid interactions in model membrane systems.

Z Mirghani·D Bertoia·A Gliozzi·M De Rosa·A Gambacorta

View original source ↗Export metadata ↓

Abstract

1H-NMR, dynamic light scattering and negative staining electron microscopy have been used to study the formation and physico-chemical properties of aqueous dispersions of mixtures of monopolar lipids extracted from Sulfolobus solfataricus. This microorganism is a thermophilic archaeobacterium growing optimally at about 85 degrees C and pH 3. The two hydrolytic fractions of the membrane complex lipids that have been studied are: the symmetric lipid glycerol dialkyl glycerol tetraether (GDGT) and the asymmetric lipid glycerol dialkyl nonitol tetraether (GDNT). Electron micrographs of pure and mixed GDNT and GDGT dispersions show the formation of complex structures. Only above a critical monopolar/bipolar lipid ratio, typical of the bipolar lipid, could closed structures be formed and good agreement was obtained in sizing with NMR, electron microscopy and dynamic light scattering. NMR spectra have been carried out at several temperatures from 25 degrees to 85 degrees C, to obtain information on the temperature-dependent structural, dynamic and permeability properties of the co-dispersed vesicles. The results are discussed in terms of the steric constraints and the chemico-physical interactions occurring among the different parts of the molecules and compared with previous studies performed with different physical techniques.

Explore related subjects

Glyceryl Ethers Lanthanum Light Lipid Metabolism Lipids Liposomes Magnetic Resonance Spectroscopy Membranes, Artificial Microscopy, Electron Osmolar Concentration Phosphatidylcholines Scattering, Radiation Thermodynamics Journal Article Research Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Z Mirghani, D Bertoia, A Gliozzi, M De Rosa, A Gambacorta. 1990. Monopolar-bipolar lipid interactions in model membrane systems.. https://doi.org/10.1016/0009-3084(90)90069-4

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Synthesis and characterization of nonconventional surfactants of aromatic amino acid-glycerol ethers: effect of the amino acid moiety on the orientation and surface properties of these soap-type amphiphiles.

The synthesis, characterization, and surface properties of soap-type amphiphiles comprising alkyl chains of 10-16 carbon atoms linked through an ether group to a glycerol-amino acid hydrophilic head group is described. The surface properties of members of this series derived from histidine and tyrosine were compared with those of phenylalanine and tryptophan derivatives described previously and with those of conventional soaps. In all cases, the amino acid derivatives showed superior surface properties, and an interesting differentiation was discovered regarding the orientation of tryptophan derivatives.

Glyceryl Ethers↗

PubMed1991

Liposome formation from synthetic polyhydroxyl lipids.

The preparation of liposomes from synthetic dialkyl amphiphiles is described. Two of these lipids were synthesised with mixed chains of 18:0,14:0 and 18:0,22:0 and one contained two identical alkyl chains of 18:0,18:0. Based on electron microscopic observations and encapsulation studies, liposomes formed from these lipids resemble those prepared from natural lipids. The polyhydroxyl head group of these lipids was designed to mimic the oligosaccharide rich surface of natural cells. SPLVs of all lipid compositions investigated, had higher encapsulation efficiency compared with that of MLVs. With SPLVs the encapsulation efficiency obtained with EPC liposomes were similar to those with novel lipids. However, the optimum was obtained with 4a:cholesterol. Encapsulation efficiency in both MLVs and SPLVs was higher with novel lipid containing different side chain length.

Glyceryl Ethers↗

PubMed1988

Substrate specificity of Staphylococcus aureus (TEN5) lipases with isomeric oleoyl-sn-glycerol ethers as substrates.

For the first time fully protected substrates with only one hydrolyzable ester bond have been used to analyze the substrate specificity of microbial lipases. In these substrates the ester is attached to the glycerol molecule in a precisely defined position. The use of three different substituents generates chirality and thus allows the analysis of positional specificities of individual lipases. Therefore, these new substrates have been used to study the enzymatic activities of two closely related lipases isolated from Staphylococcus aureus (TEN5) designated the 44 and 43 kDa lipase. The lipases, especially the 44 kDa molecule, show a high specificity for the hydrolysis of the ester in the sn-1 position (S-configuration), which is hydrolyzed by a factor of ten faster than that in the sn-3 position. In addition, the study demonstrates for the first time that the rate of hydrolysis of a fatty acid ester attached to the sn-2 position of glycerol by microbial lipases depends on the configuration of the substrate molecule.

Glyceryl Ethers↗