The effect of Al3+ on the physical properties of membrane lipids in Thermoplasma acidophilum

Abstract

Using Electron Paramagnetic Resonance Spectroscopy, Al3+ was shown to produce a dramatic decrease of membrane lipid fluidity on the microorganism Thermoplasma acidophilum at a pH > 2. The ability of Al3+ to alter lipid fluidity was enhanced with increasing pH (from 3 to 5). At pH 4, 10-2 M Al3+ increased the lower lipid phase transition by 39°C, and a detectable change was observed with AlCl3 concentrations as low as 10-5 M. The ability of Al3+ to increase the lower lipid phase transition temperature of T. acidophilum is the largest of any cation/lipid interaction yet reported. © 1978.