DIRECT MEASUREMENT OF FORCES BETWEEN MEMBRANES OR MACROMOLECULES

直接测量膜之间的力的能力， 正在创造一种新的逻辑来思考 分子识别、组装和折叠。 突出的特点 当分子或膜接近接触时， 方法的重要工作包括除去有机水溶剂 从相对的表面。 这些“水化力量”现在 被认为在脂质双层、蛋白质、DNA等多种材料中起作用 双螺旋和硬多糖。 本年度A 第一次直接测量蛋白质分子之间的力（I型 胶原蛋白三螺旋）已经成功。 已显示 力具有水化力的所有特征。 的 力的温度依赖性类似于 DNA分子的有序排列。 这表明， 在DNA和蛋白质中的温度偏好组装可能是相似的。 温度优势组装是许多生物学上的共同特征， 重要进程。 温度促进组装理论 由亲水性分子之间的吸引水合力引起 开发了 之间的相互作用力测量 双十六烷基二甲基乙酸铵双层已经证明， 既没有热机械波动也没有分子突起 对脂质双层之间的水合力有显著贡献。

The ability to measure directly the forces between membranes or between macromolecules is creating a new logic for thinking about molecular recognition, assembly, and folding. The outstanding feature of interaction is 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 now recognized to act in materials as diverse as lipid bilayers, proteins, DNA double helices, and stiff polysaccharides. During the current year a first direct measurement of forces between protein molecules (type I collagen triple helices) has succeeded. It has been shown that the force has all the features characteristic of hydration forces. The temperature dependence of the force is similar to that observed in ordered arrays of DNA molecules. This shows that physical nature of temperature-favored assembly in DNA and proteins might be similar. Temperature-favored assembly is a common feature of many biologically important processes. The theory of temperature-favored assembly induced by attractive hydration forces between hydrophilic molecules has been developed. Measurement of interaction forces between dihexadecyldimethylammonium acetate bilayers has demonstrated that neither thermal-mechanical undulations nor molecular protrusions contribute significantly to hydration forces between lipid bilayers.