Raman Research Institute, C V Raman Avenue, Sadashivanagar, Bangalore, 560 080, India.
Eur Biophys J. 2012 Oct;41(10):891-900. doi: 10.1007/s00249-012-0823-7. Epub 2012 Jun 6.
Oxysterols are oxygenated derivatives of cholesterol that form a class of potent regulatory molecules with diverse biological activity. Given the implications of oxysterols in several physiological/pathophysiological pathways of human diseases, it is important to identify how their presence affects the biophysical properties of cell membranes. In this article we first describe the structure, formation, and biological functions of oxysterols, and previous work on the effect of these molecules on the structure and phase behavior of lipid membranes. We then present results of our X-ray diffraction experiments on aligned multilayers of dipalmitoylphosphatidylcholine (DPPC) membranes containing ring-substituted oxysterols. The effect of these molecules on the phase behavior of DPPC membranes is found to be very similar to that of cholesterol. All the oxysterols studied induce a modulated phase in DPPC membranes, similar to that reported in DPPC-cholesterol membranes. However, some differences are observed in the ability of these molecules to suppress the main transition of the lipid and to induce chain ordering, which might be related to differences in their orientation in the bilayer.
氧化固醇是胆固醇的含氧衍生物，形成了一类具有多种生物学活性的强效调节分子。鉴于氧化固醇在人类疾病的几种生理/病理生理途径中的意义，确定它们的存在如何影响细胞膜的生物物理特性非常重要。在本文中，我们首先描述了氧化固醇的结构、形成和生物学功能，以及以前关于这些分子对脂质膜结构和相行为影响的工作。然后，我们介绍了我们在含有环状取代氧化固醇的二棕榈酰磷脂酰胆碱（DPPC）膜的取向多层膜上的 X 射线衍射实验结果。这些分子对 DPPC 膜相行为的影响与胆固醇非常相似。所有研究的氧化固醇都诱导 DPPC 膜形成调制相，类似于 DPPC-胆固醇膜中报道的相。然而，在这些分子抑制脂质主转变和诱导链有序化的能力方面观察到一些差异，这可能与它们在双层中的取向差异有关。
