Ca2+-induced changes in the barrier properties of cardiolipin/phosphatidylcholine bilayers.
(1) A selective increase in permeability is induced in cardiolipin/phosphatidylcholine bilayers at Ca2+ concentrations of 1--3 mM. At higher concentrations of Ca2+ the permeability barrier is completely destroyed. (2) The selective increase in permeability is correlated with the formation of lipid particles visualized by freeze-fracture electron microscopy and an isotropic signal in 31P-NMR spectra. (3) Lowering the Ca2+ concentration shows reduction in permeability but the formation of the lipid particles is a non-reversible process. (4) At higher Ca2+ concentrations, 31P-NMR spectra and freeze-fracture results indicate the formation of the hexagonal phase, explaining the disappearance of the permeability barrier.
D002118:Calcium; D002308:Cardiolipins; D005614:Freeze Fracturing; D008051:Lipid Bilayers; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008968:Molecular Conformation; D010539:Permeability; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D011188:Potassium
D002308:Cardiolipins; D008051:Lipid Bilayers; D010712:Phosphatidic Acids; D010713:Phosphatidylcholines; D011188:Potassium; D002118:Calcium