Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76110, Israel.
Chem Phys Lipids. 2011 Oct;164(7):672-9. doi: 10.1016/j.chemphyslip.2011.06.012. Epub 2011 Jul 6.
An oxidized form of cholesterol, atheronal, is a form found in vivo that has been associated with human pathologies. We have studied mixtures of this oxidized sterol with the phospholipids phosphatidylethanolamine and phosphatidylcholine. We used phospholipids either with palmitoyl and oleoyl acyl chains on the C1 and C2 carbon atoms of glycerol or with both acyl chains being palmitoleoyl. We also compared the effects of atheronal on the curvature properties of these lipids with the action of cholesterol. We studied the bilayer to hexagonal phase transition temperature of mixtures of these lipids using differential scanning calorimetry as well as the dimensions of the hexagonal phase cylinders using X-ray diffraction. Disordering of the lamellar phase was also qualitatively assessed by the loss of sharp diffraction peaks. Our results demonstrate that the modulation of membrane curvature in these systems depends not only on the nature of the sterol, but also on the acyl chain composition of the phospholipids used. In addition, some of the effects of atheronal could be ascribed to reaction of the aldehyde and ketone groups of this oxidized sterol with the amino group of phosphatidylethanolamine.
胆固醇的氧化形式，atheronal，是一种在体内发现的形式，与人类病理学有关。我们研究了这种氧化固醇与磷脂酰乙醇胺和磷脂酰胆碱的混合物。我们使用了棕榈酰和油酰酰链在甘油的 C1 和 C2 碳原子上的磷脂，或者两个酰链都是棕榈油酸酰链。我们还比较了 atheronal 对这些脂质曲率性质的影响与胆固醇的作用。我们使用差示扫描量热法研究了这些脂质混合物的双层到六方相转变温度，以及使用 X 射线衍射研究了六方相圆柱的尺寸。通过尖锐衍射峰的消失，也定性地评估了层状相的无序。我们的结果表明，这些系统中膜曲率的调节不仅取决于固醇的性质，还取决于所用磷脂的酰链组成。此外，atheronal 的一些作用可以归因于这种氧化固醇的醛和酮基团与磷脂酰乙醇胺的氨基之间的反应。
