Lipid--DNA interactions. II. Phospholipids, cholesterol, glycerophosphorylcholine, spingosine and fatty acids

High concentrations of lecithin, phosphatidylethanolamine, phosphatidylserine, cholesterol and lauric acid have a destabilizing effect on the DNA helix. On the contrary, lower concentrations of the same lipids produce stabilization on DNA. The stabilizing and destabilizing effects with sphingomyelin components can be mainly attributed to sphingosine and lignoceric acid components, whereas glycerophosphorylcholine probably has a minimal effect. The saturated long-chain fatty acids (C 18:0 , C 24:0 ) were capable of having a moderate destabilizing effect on DNA; however, the unsaturated fatty acids were found to be generally more stabilizing in nature. The type of bonding within the lipid-DNA interaction has been investigated and the existence of a lipid-DNA complex in vivo has been considered.