CATIONIC ATMOSPHERE AND CATION COMPETITION BINDING AT NEGATIVELY CHARGED MEMBRANES - PATHOLOGICAL IMPLICATIONS OF ALUMINUM

Abstract

Binding of cations to membranes may be the basis for explaining some of the effects of several neurotoxic cations. The binding of Al3+ and the displacement of Ca2+ by Al3+ is studied with the aid of a simple mathematical approach described here. The method allows the simulation of membranes with low surface charge densities that are relevant for biochemical and pathological implications. Fluorescence quenching of the phospholipid analogue 1-palmitoyl-2-nitrobenzoxadiazol amino caproyl- phosphatidyl choline (C6-NBD-Ptd Cho) embedded in phosphatidyl serine membranes is ued to determine the competition between Ca and Al for binding. The effect of Al in the presence of chelating agents is also studied by quencing experiments. Finally, inhibition of 45Ca2+ binding to phosphatidyl serine has also been investigated in a 2-phase system.