Localization of dolichols in phospholipid membranes. An ESR spin label study

We have used ESR methods employing spin-labeled stearates to investigate the effects of dolichol on the motion of lipid molecules in phospholipid membranes of phosphatidylethanolamine and phosphatidylcholine. The ESR spectra show that the presence of dolichol affects the motion of the spin probes at carbon-16, but not at carbon-5. Similar results are obtained with phospholipid membranes comprising only phosphatidylcholine. It is suggested that dolichol molecules are present mainly in the lipid core region of phospholipid membranes.