Acyl chain order and lateral domain formation in mixed phosphatidylcholine--sphingomyelin multilamellar and unilamellar vesicles.
Acyl chain order and lateral domain formation in mixed phosphatidylcholine--sphingomyelin multilamellar and unilamellar vesicles.
复制标题
混合磷脂酰胆碱-鞘磷脂多层和单层囊泡中的酰基链顺序和侧向结构域形成。
DOI：
10.1021/bi00527a010
复制
发表时间：
1981
期刊：
影响因子：
2.9
通讯作者：
Barenholz,Y
中科院分区：
文献类型：
--
作者：
Lentz,BR;Hoechli,M;Barenholz,Y
巴里河Lentz，* Mathias Hoechli，and Yecheskael Barenholz摘要：研究了二肉豆蔻酰磷脂酰胆碱（DMPC）与V-棕榈酰鞘氨醇磷酸胆碱（Ci 6SPH）混合物在小单层和大多层囊泡中的相行为。用1，6-二苯基-1，3，5-己三烯（DPH）的稳态荧光偏振法研究了温度对膜结构的影响。此外，电子显微镜还发现，在不同温度下喷射冷冻的大多层囊泡的囊面形态有很大的不同。这些数据已被interpreted在此脂质混合物的建议阶段。拟议的相图的形状使我们得出结论，磷脂酰胆碱和鞘磷脂物种的类似的酰基链长自由混合在高度弯曲和非弯曲的双层，除了在温度下，这两种脂质在低温，有序相。此外，这些相图与纯磷脂酰胆碱的类似混合物的相图的相似性表明，鞘磷脂和磷脂酰胆碱在支持细胞膜结构所必需的层状相时可能相互取代。最后，DPH荧光的各向异性被发现是基本上invariantwith鞘磷脂含量在温度刚好高于和低于小单层囊泡中的固-液相分离。这表明鞘磷脂骨架本身并不排列膜双层。这些结果讨论了鞘磷脂在控制细胞膜内酰基链序中的可能作用。哺乳动物膜的许多组分磷脂的e相行为已在以下文献中得到广泛研究：生物化学系（BRL）和解剖学系（MH），北卡罗来纳大学查佩尔山，查佩尔山，北卡罗来纳州27514，以及希伯来大学哈达萨医学院生物化学系（YB），以色列耶路撒冷。1981年5月5日收到。这项研究得到了美国国家科学基金会（PCM 76-16761和PCM 79-22733）、美国公共卫生署（HL 17576）和美国-以色列两国科学基金会（1688）的赠款。BRL是美国心脏协会颁发的研究者奖的获得者，部分资金由北卡罗来纳州心脏协会提供。1981年在美国科罗拉多州丹佛市召开的生物物理学会会议上提出了这项工作的初步报告，目的是确定不同磷脂种类在建立膜结构中的作用。虽然某些物种形成非层状相的能力可能对专门的膜功能很重要（Cullis& DeKruijff，1979），但那些在水中自发形成层状介晶相的物种应该稳定细胞膜的基本双层结构。胆碱、磷脂、磷脂酰胆碱和鞘磷脂是哺乳动物细胞膜的主要成分，它们在过量的水中形成层状相。这两种脂质比例的变化与各种组织功能障碍的发生相关（Barenholz和Thompson，1980），例如衰老（Barenholz和所罗门，1969）、动脉粥样硬化（Small和Shipley，
Barry R. Lentz,* Mathias Hoechli, and Yecheskael Barenholz abstract: The phase behavior of mixtures of dimyristoyl-phosphatidylcholine (DMPC) with V-palmitoylsphingosinephosphorylcholine (Ci6SPH) has been investigated in both small unilamellar and large multilamellar vesicles. The steady-state fluorescence polarization of 1, 6-diphenyl-1, 3, 5-hexatriene (DPH) has been used to detecttemperature-induced structural changes in these membranes. In addition, electron microscopy has revealed vastly different fracture-face mor-phologies for large multilamellar vesicles “jet-frozen” from different temperatures. These data have been iriterpreted in terms of proposed phase diagramsfor this lipid mixture. The shapes of the proposed phase diagrams have led us to conclude that phosphatidylcholine and sphingomyelin species of similar acyl chain length mix freely in both highly curved and un-curved bilayers, except at temperatures at which both lipids are in low-temperature, ordered phases. In addition, the similarity of these phase diagramsto phase diagrams for analogous mixtures of pure phosphatidylcholines suggested that sphingomyelin and phosphatidylcholine species might sub-stitute for each other in supporting the lamellar phase nec-essary to cell membrane structure. Finally, the anisotropy of DPH fluorescence was found to be essentially invariantwith sphingomyelin content at temperatures just above and below the solid-liquid phase separation in small unilamellar vesicles. This demonstrates that the sphingomyelin backbone, per se, does not order the membrane bilayer. These results are dis-cussed in terms of the possible role of sphingomyelin in con-trolling acyl chain order withiri mammaliancell membranes. e phase behavior of many of the component phospholipids of mammalian membranes has been studied extensively in f From theDepartments of Biochemistry (BRL) and Anatomy (MH), University of NorthCarolina at Chapel Hill, Chapel Hill, North Carolina 27514, and the Department of Biochemistry (YB), The He-brew University, Hadassah Medical School, Jerusalem, Israel. Received May 5, 1981. This investigation was supported by grants from the National Science Foundation (PCM 76-16761 and PCM 79-22733), the US Public Health Service (HL17576), and the US-Israel Binational Science Foundation (1688). BRL is a recipient of an Established Investigator award from the American Heart Association with funds contributed in part by the North Carolina Heart Association. A pre-liminary account of this work was presented at the 1981 meeting of the Biophysical Society in Denver, CO. recent years with a view toward defining the role of different phospholipid species in establishing membrane structure. While the ability of some species to form nonlamellar phases may be important tospecialized membrane functions (Cullis& DeKruijff, 1979), those species that spontaneously form lamellar mesomorphic phases in water should stabilize the essential bilayer structure of cell membranes. The choline phosphatides phosphatidylcholine and sphingomyelin are major components of mammalian membranes that form lamellar phases in excess water. Changes in the ratio of these two lipids have been correlated with the occurrence of various tissue malfunctions (Barenholz & Thompson, 1980) such as aging (Rouser & Solomon, 1969), atherosclerosis (Small & Shipley,