高等学校化学学报 ›› 2009, Vol. 30 ›› Issue (5): 913-918.

• 研究论文 • 上一篇    下一篇

DOPC, DOPE和神经酰胺对鞘磷脂/胆固醇双层膜结构的影响

郝长春1, 孙润广1, 张静2   

    1. 陕西师范大学物理学与信息技术学院生物物理与生物医学工程研究室,
    2. 食品工程与营养科学学院, 西安 710062
  • 收稿日期:2008-10-28 出版日期:2009-05-10 发布日期:2009-05-10
  • 通讯作者: 孙润广, 男, 博士, 教授, 博士生导师, 主要从事生物物理与生物医学工程研究, E-mail: sunrunguang@snnu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 20772077)、教育部科学技术研究重点项目(批准号: 104167)和陕西师范大学研究生创新基金(批准号: 2008CXB012)资助.

Influence of DOPC, DOPE and Ceramide on the Organization of Sphingomyelin/Cholesterol Bilayers

HAO Chang-Chun1, SUN Run-Guang1*, ZHANG Jing2   

    1. Laboratory of Biophysics and Biomedical Engineering, College of Physics and Information Technology,
    2. College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi′an 710062, China
  • Received:2008-10-28 Online:2009-05-10 Published:2009-05-10
  • Contact: SUN Run-Guang, E-mail: sunrunguang@snnu.edu.cn

摘要:

用LB技术和原子力显微镜(AFM)研究了1,2-二油酸甘油-3-磷脂酰胆碱(DOPC)、1,2-二油酸甘油-3-磷脂酰乙醇胺(DOPE)和神经酰胺(Ceramide)对鞘磷脂(SM)/胆固醇(Chol)结构的影响. 实验结果表明, 在表面压力较低时, 每种混合脂双层膜都呈现均匀分布的脂双层结构. 随着表面压力的增加, 形态发生了明显的变化: (1) SM/Chol二元组分双层膜形成均一的液态有序相微区结构, 衬底覆盖率达到80%; (2) DOPC的加入促使SM/Chol双层膜出现相分离现象, SM/Chol形成的液态有序相 “岛状” 微区结构漂浮在液态无序相的DOPC上部, 约占总面积的30%; (3) DOPE与SM/Chol形成的双层膜明显不同于DOPC/SM/Chol, 呈现出液态无序相、液态有序相及凝胶相3相共存的结构; (4) Ceramide诱导了SM/Chol双层膜结构发生重排, 两层脂分子间发生翻转形成囊泡结构, 部分神经酰胺从液态有序相中分离形成小颗粒结构. 在较高膜压下, 各系统都呈现出具有特定形态的双层膜结构. 分子官能团的成键能力决定了双层膜形态结构.

关键词: 脂筏, LB膜技术, 原子力显微镜, 相分离

Abstract:

Lipid rafts are of a dynamic microdomain structure found in recent years, enriched in signal molecules. The change of structure and function of lipid rafts can result in many diseases. LB technique and atomic force microscopy were used to study the effect of 1,2-dioleoy-sn-glycero-3-phosphocholine(DOPC), 1,2-dioleoy-sn-glycero-3-phosphoethanolamine(DOPE) and ceramide on the structure of sphingomyelin(SM)/Cholesterol LB bilayers. We found that each bilayer of lipid mixtures took on uniform distribution bilayer structure when the surface pressure was low. When increasing the surface pressure, great changes were taken place on the bilayers: (1) The bilayers composed of SM/Chol appeared uniform liquid-ordered microdomains structure, with coverage of 80% of mica. (2) In SM/Chol/DOPC bilayers, the liquid-ordered microdomains formed by SM/Chol floated onto the fluid-disordered small DOPC granule, about 30% coverage. (3) When adding DOPE to SM/Chol, the bilayers had changed obviously, meanwhile liquid-disordered, liquid-ordered and gel phases coexisted on the mica. (4) The Ceramide induced the bilayers of SM/Chol rearrangement, the lipids of bilayers occurred flip-flop to form vesicle structure. At the higher surface pressure, all the systems could form specific platform structure. The bond capabilities of molecular groups play an important role in forming structure.

Key words: Lipid raft, LB technique, Atomic force microscopy(AFM), Phase separation