MICROSTRUCTURAL HETEROGENEITY IN MEMBRANES

膜的微观结构异质性

• 批准号: 2611776
• 负责人: Barry R Lentz
• 金额: $ 3.95万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-12-01 至 1998-04-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2611776
• 关键词: chimeric proteins; cholesterol; ethylene glycols; fluorescent dye /probe; infrared spectrometry; interferometry; light scattering; lipid bilayer membrane; membrane fusion; membrane lipids; membrane permeability; membrane structure; microorganism hemagglutinin; molecular asymmetry; molecular polarity; molecular shape; nuclear magnetic resonance spectroscopy; phase change; phosphatidylcholines; phosphatidylethanolamines; thermodynamics

Poly(ethylene glycol) (PEG) is used widely to mediate cell-cell fusion in the production of somatic cell hybrids and in the fusion injection of macromolecules into cultured cells from erythrocytes or liposomes. However, little is known about the mechanism by which PEG induces fusion of cell membranes. The proposed research will continue to examine in molecular detail the influence of PEG on phospholipid vesicles as a model for events in more complex biological membranes. The primary is to elucidate the mechanism of PEG-mediated membrane fusion. The information obtained will be useful for advancing PEG- mediated cell fusion technologies as well as for providing clues to the molecular mechanism of in vivo cell fusion processes such as endocytosis, exocytotic excretion, protein sorting and transport, and viral budding and infection. Work of the past grant period led to a hypothesis for the mechanism of PEG-mediated fusion: formation of fusion intermediates occurs when bilayers containing fluctuational lipid packing defects in the glycerol backbone region are brought into molecular contact by the dehydrating influence of PEG. The resulting probability of fusion is proportional to both the probability of critical inter-bilayer approach and to the probability of packing disruption in either the inner or outer leaflet of the bilayer. The proposed experiments are organized into six aims that will test and then apply this hypothesis to increasingly more complex membranes including ones treated with a viral fusion peptide and cultured cell membranes: 1] test several bilayer components and bilayer conditions for fusogenicity; 2] elaborate the bilayer structural characteristics associated with fusion; 3] test for a critical bilayer structure that seems to correlate with fusion; 4] using several spectroscopic approaches, test whether there exists a common perturbation in bilayer packing associated with PEG-mediated fusion of different model membranes; 5] examine how a very small quantity of the N-terminal "fusion peptide" of influenza virus hemagglutinin induces fusion of membranes aggregated by low concentrations of PEG; and 6] determine whether bilayer perturbants that act as fusogens in model membranes will increase the efficiency of PEG-mediated fusion of cultured cells.

聚乙二醇 (PEG) 广泛用于介导细胞间融合 在体细胞杂交体的生产和融合注射中 将大分子从红细胞或脂质体转化为培养细胞。 然而，人们对 PEG 诱导的机制知之甚少。 细胞膜的融合。 拟议的研究将继续 在分子细节上检查 PEG 对磷脂的影响 囊泡作为更复杂生物膜中事件的模型。 主要是阐明PEG介导的膜的作用机制 融合。 获得的信息将有助于推进 PEG- 介导的细胞融合技术以及提供线索 体内细胞融合过程的分子机制，例如 内吞作用、胞吐排泄、蛋白质分选和运输，以及 病毒出芽和感染。 过去资助期的工作提出了一个关于机制的假设 PEG介导的融合：融合中间体的形成发生在以下情况： 甘油中含有波动脂质堆积缺陷的双层 主链区域通过脱水而形成分子接触 PEG 的影响。 融合的概率成正比 临界双层间方法的概率和 内叶或外叶包装破裂的概率 双层的。 拟议的实验分为六个目标 将测试这一假设，然后将其应用到越来越多的领域 复杂的膜，包括用病毒融合肽处理的膜 和培养的细胞膜：1]测试几种双层成分和 融合性的双层条件； 2]详细阐述双层 与融合相关的结构特征； 3]测试 似乎与融合相关的关键双层结构； 4] 使用多种光谱方法，测试是否存在 与 PEG 介导相关的双层堆积中的常见扰动 不同模型膜的融合； 5]检查一个非常小的 流感病毒N端“融合肽”的数量 血凝素诱导低浓度聚集的膜融合 PEG浓度；和6]确定双层扰动是否 在模型膜中充当融合剂将提高效率 PEG 介导的培养细胞融合。