Interaction of Zn²⁺Ions with Phospholipid Multilayers

Abstract

Phospholipids are large natural amphipathic molecules which, in contact with water, assemble into higher molecular aggregates. The most relevant one is the bilayer for its relation to the structure, properties and functions of cell membranes. Given their structural complexity phospholipid bilayers are usually used as models for studying how biologically relevant chemicals affect the structure and functions of biomembranes. Zn is a trace element essential for the functional integrity of cell membranes. It is also a common contaminant of sea waters. Therefore, it was thought of interest to study the interaction of ZnZ+ ions with phospholipid bilayers in order to understand the way they interact with cell membranes. With this aim Zn2+, in a wide range of concentrations, was made to interact with multibilayers of the phospholipids dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE). This study was performed by X-ray diffraction. Besides, the interaction of Znz+ with DMPC liposomes was studied by fluorescence spectroscopy. The results showed that indeed Zn2+ interacted with both phospholipids. As its concentration increased it produced first a disorder effect which was reversed at higher concentrations.

Cadmium-induced changes in the membrane of human erythrocytes and molecular models

“…It therefore can be concluded that the toxicity of Cd 2þ is not specific at the membrane level and it is exerted by several mechanisms. A comparison of the effects of Cd 2þ with the effects of Cu 2þ , Zn 2þ , Hg 2þ and Pb 2þ ions on phospholipid bilayers, DMPC LUV and IUM clearly shows that Cd 2þ , followed by Pb 2þ , induced the highest structural perturbation in all these systems [11,12,14,15]. These results agree with the recognition of cadmium as one of the most toxic environmental pollutants [8,23].…”

“…Intact human erythrocytes incubated with the metal ions were observed by scanning electron microscopy (SEM) while their IUM and DMPC LUV were studied by fluorescence spectroscopy. These systems and techniques have been used in our laboratories to determine the interaction with and the membrane-perturbing effects of other metal ions such as Zn 2þ [11], Cu 2þ [12], Hg 2þ [13], Al 3þ [14], and Pb 2þ [15].…”

Structural effects of titanium citrate on the human erythrocyte membrane

“…Intact human erythrocytes incubated with this compound were observed by scanning electron microscopy (SEM) while their IUM and DMPC LUV were studied by fluorescence spectroscopy. These systems and techniques have been used in our laboratories to determine the interaction with and the membraneperturbing effects of other metal ions such as Zn 2+ [11], Cu 2+ [12], Hg 2+ [13], Al 3+ [14], Pb 2+ [15] and Cd 2+ [16].…”