MEMBRANE MEDIATED PROTEIN INTERACTION

膜介导的蛋白质相互作用

• 批准号: 8170062
• 负责人: THOMAS F WEISS
• 金额: $ 0.44万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170062
• 关键词: Biological Models; Computer Retrieval of Information on Scientific Projects Database; Data; Defect; Dependence; Funding; Grant; Institution; Length; Lipids; Mediating; Membrane; Membrane Lipids; Modeling; Peptides; Proteins; Research; Research Personnel; Resources; Sampling; Source; Structure; Surface; Thick; United States National Institutes of Health; Water; liquid crystal; millimeter; research study; silicon nitride; transmission process

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In the presence of water aligned lipid membranes self-assemble in the vicinity of flat and smooth surfaces forming a smectic-C liquid crystal structure with water intercalated between the bilayers formed by the lipid molecules. By sandwiching hydrated lipids in between two substrates one can achieve several square-millimeter large defect-free monodomains of highly aligned lipid membranes. Using thin silicon-nitride windows as alignment substrate transmission SAXS experiments on such samples are possible. The small size and high intensity of the beam available at bealine 4-2 together with the large defect free domain size allows to probe the structure in the plane of the membrane. In this project we investigated the change in the nearest neighbor distance between membrane embedded peptides in dependence on the thickness of the lipid and the peptide concentration. We find that the average distance between the proteins increases with increasing thickness of the bilayer. This effect is attributed to the increased membrane mediated repulsive interaction between the peptides due to the increased hydrophobic mismatch. The data can be fitted using the product of the known formfactor of the peptide and a theoretical structure factor calculated assuming hard-core repulsion between the embedded peptides. The hard core repulsion was found to be an adequate model for the system with the shortest lipid chains. An increase in the lipid chain length producing a mismatch between the hydrophobic lengths of the peptide and the lipid causes the onset of longer ranged, membrane mediated forces between the peptides. In order to include these additional forces into the hard-core structure factor a perturbation extension of the current model is currently being pursued.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 在水的存在下，取向的脂质膜在平坦和光滑的表面附近自组装，形成近晶-C液晶结构，其中水插在由脂质分子形成的双层之间。通过将水合脂质夹在两种基质之间，可以获得高度对齐的脂质膜的几平方毫米大的无缺陷单域。使用薄的氮化硅窗口作为对准衬底的传输SAXS实验对这样的样品是可能的。在Bealine 4-2处可用的小尺寸和高强度的光束与大的无缺陷域尺寸一起允许探测膜平面中的结构。在这个项目中，我们研究了膜嵌入肽之间的最近邻距离的变化依赖于脂质的厚度和肽浓度。我们发现，蛋白质之间的平均距离增加的双层厚度。这种效应归因于由于疏水性错配增加而增加的膜介导的肽之间的排斥相互作用。可以使用肽的已知形状因子和理论结构因子的乘积来拟合数据，所述理论结构因子假设嵌入的肽之间的硬核排斥而计算。硬核排斥被认为是一个适当的模型与最短的脂链的系统。脂质链长度的增加产生肽和脂质的疏水长度之间的错配，导致肽之间的较长范围的膜介导力的开始。为了将这些额外的力纳入核心结构因子，目前正在对当前模型进行扰动扩展。