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V Luzzati

Publications and source records attributed to V Luzzati.

At least 37 records · Page 2Linked to original sources
PubMed1978

The influence of protein-lipid interactions on the order-disorder conformational transitions of the hydrocarbon chain.

The phases of simple systems involving one type of protein (lysozyme or cytochrome c) and one type of lipid (phosphatidic acid) have been characterized by X-ray crystallography, chemical analysis and spin-labeling technique as a function of temperature. They are of the lamellar type with alternative protein monolayers and lipid bilayers. According to the pH, two types of lamellar phases are obtained, one where the lipid-protein interactions are mainly hydrophobic, the other where they are electrostatic. In both cases, a phase transition occurs as temperature is lowered, between a high temperature phase, where all the lipids are in the liquid-like state, and another phase where some lipid chains are rigid. In the case of the phases with electrostatic interaction, it is shown that the onset of the order-disorder transition is shifted towards low temperature as compared with the homologous lipid-water phase and that the protein content of the phase decreases as the ratio of the liquid to rigid hydrocarbon chains decreases. This leads us to suggest that in the systems studied in this work the proteins interact only with lipid in the liquid-like state. In the case of the phases with hydrophobic interaction, it is shown that the extent of hydrophobic interaction between protein and lipid increases as the unsaturation of the hydrocarbon chains increases. The onset of the order-disorder transition shows a greater shift towards low temperature than the one observed in the case of the phase with electrostatic interaction.

Cytochrome c Group↗
PubMed1977

A novel packing of the hydrocarbon chains in lipids. The low temperature phases of dipalmitoyl phosphatidyl-glycerol.

The system dipalmitoyl phosphatidylglycerol-water displays several phases in the temperature-concentration range explored in this work. All the phases are lamellar; they differ by the organization of the hydrocarbon chains. In the high temperature phase the conformation of the chains is liquid-like. In the low temperature phases the chains are stiff and parallel and they interdigitate (in other words the CH3 ends of the chains of one layer are near to the polar groups of the opposite layer). Moreover, several types of packings of the stiff chains are observed which differ by the symmetry of the two-dimensional lattices. The observed lattices are p6, cmm and pgg.

Molecular Conformation↗
PubMed1975

Neutron scattering study of human serum low density lipoprotein.

Regions of different proton density in the low density lipoprotein (LDL) particle from human serum have been determined by neutron scattering. From measurements in various H2O/D2O mixtures, the LDL particle appears to be quasi-spherical, with the centers of gravity of the hydrocarbon and polar regions coinciding. The average volume occupied by a particle was found to be 3.2 X 10-6 A-3, with the volume fraction occupied by the hydrocarbons being 60%. The ratius of gyration of the hydrocarbon region was 64 A, while that of the polar region was 100 A. consequently, the core of LDL is predominantly occupied by the hydrocarbon chains, while the outer shell is sparsely occupied by protein emerging from the lipid core.

Deuterium↗