Impact of Coenzyme Q10 on the Physical Properties of Model Lipid Membranes

Abstract

We investigated the influence of coenzyme Q₁₀ on structural changes of model lipid membranes formed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and by a mixture of phosphatidylcholine and sphingomyelin (2.4:1). Structural changes in the membranes were measured using electron paramagnetic resonance and differential scanning calorimetry. Two spin probes were used to monitor membrane characteristics: MeFASL (10,3) to monitor the changes close to the water-lipid interface, and MeFASL (2,11) to monitor the changes in the middle of the bilayer of the model lipid membranes. These data show that perturbation of CoQ₁₀ in the lipid membranes, promotes a decrease in the dynamics of the lipid acyl chains, i.e., it increases the ordering of the membrane interior. The results from DSC measurements suggested that the CoQ₁₀ in the bilayer does not significantly perturb the thermal and enthalpic stability of DPPC (the gel-to-liquid transition does not change) but additionally stabilizes the lipid bilayer due to the aggregation of CoQ₁₀ within the lipid bilayer. The CoQ₁₀ fraction in an aggregated state increased in proportion to its concentration in the DPPC multilamellar liposomes.