DIRECT MEASUREMENT OF FORCES BETWEEN MEMBRANES OR MACROMOLECULES

直接测量膜或大分子之间的力

• 批准号: 3774973
• 负责人: V A PARSEGIAN
• 金额: --
• 依托单位: CENTER FOR INFORMATION TECHNOLOGY
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3774973
• 关键词: acidity /alkalinity; chemical binding; chemical hydration; collagen; intermolecular interaction; ionic bond; lipid bilayer membrane; macromolecule; measurement; membrane activity; molecular biology; osmotic pressure; protein biosynthesis; protein reconstitution; quaternary ammonium compound; temperature

Use of the Osmotic Stress method, developed by our group to measure directly forces between membranes or between macromolecules, has spread rapidly this past year to several laboratories in Europe and North America. One result of this recent proliferation in practice has been to advance the idea that as molecules or membranes approach contact, the important work of approach involves removal of organized water solvent from the apposing surfaces. These "hydration forces" are increasingly recognized to act in materials as diverse as lipid bilayers, proteins, DNA double helices, and stiff polysaccharides. The growing catalog of information about interactions continues to create a new logic for thinking about molecular recognition and folding. During the current year, we have concentrated on forces between proteins, specifically examining native and reconstituted collagen fibers at various temperatures, pH, ionic conditions, and in the presence of several small solutes. It has been shown that salt does not fully penetrate into the space between collagen triple helices. Osmotic pressure applied from outside by the excluded salt is an important component of collagen fiber assembly. Force measurements have demonstrated that temperature-favored assembly of the fibers is driven by water-mediated hydrogen bonding between the apposing polar residues rather than by the hydrophobic effect usually invoked to explain assembly of proteins. One can now think of a competition between repulsive and attractive hydration forces, depending on how well protein surfaces match each other. A dependence of hydration forces between DNA molecules on small solutes, observed present in the solution, has been studied. An unusual re- entrant liquid-gel-liquid phase transition sequence, observed during measurement of forces between didodecylphosphate bilayers, has been explained. The osmotic stress technique has been extended to measure forces between spherical particles in order to create convenient models for the "molecular crowding" phenomenon important in the regime of the intracellular milieu.

使用我们小组开发的渗透应力方法来测量 膜之间或大分子之间的直接力，已扩散 去年迅速发展到欧洲和北欧的几个实验室 美国。 最近实践中这种扩散的结果之一是 提出这样的观点：当分子或膜接近接触时， 该方法的重要工作涉及去除有组织的水溶剂 从相对的表面。 这些“水合力”日益增强 公认可在脂质双层、蛋白质、 DNA双螺旋和坚硬的多糖。 不断增长的目录 有关交互的信息不断创造新的逻辑 思考分子识别和折叠。 今年，我们重点关注蛋白质之间的力量， 专门检查天然和重组胶原纤维 各种温度、pH、离子条件以及存在 几种小溶质。 事实证明，盐并不能完全 渗透到胶原蛋白三螺旋之间的空间。 渗透性 由排除的盐从外部施加的压力是一个重要的 胶原纤维组装体的组成部分。 力测量表明，有利于温度的装配 纤维的形成是由水介导的氢键驱动的 通常通过施加极性残基而不是通过疏水效应 用来解释蛋白质的组装。 现在可以想到一个 排斥力和吸引力水合力之间的竞争，取决于 蛋白质表面相互匹配的程度。 DNA 分子之间的水合力对小溶质的依赖， 观察到溶液中的存在，并进行了研究。 一次不寻常的重新 进入液体-凝胶-液体相变序列，在过程中观察到 测量双十二烷基磷酸酯双层之间的力 解释道。 渗透应力技术已扩展到测量之间的力 球形粒子，以便创建方便的模型 “分子拥挤”现象在政权中很重要 细胞内环境。