PHYSICAL PRINCIPLES OF BIOMOLECULAR RECOGNITION, SELF-ASSEMBLY & REGULATION

该项目结合了理论建模和实验室测量 确定组织背后的普遍物理原理 和不同大分子系统的功能。 的主要领域 感兴趣的是蛋白质。 在各种溶液条件下进行渗透应力测量， 这些年来的研究提供了强有力的证据，证明胶原蛋白的自组装 分子需要形成特殊的氢键水桥 在相反极性残基之间。 这些桥最有可能的位置 是两个大的，相同的，含有组氨酸的序列， 胶原蛋白分子的每一端。 结合拉曼和X射线实验表明，脱水 重组胶原纤维的变化涉及到 间隙水氢键网络;变化与 我们的水化力理论模型 为了更好地了解间隙水的特征， 胶原蛋白相互作用和自我组装的关键，我们现在已经开始 在非水溶液中胶原蛋白三螺旋之间的力的测量 具有不同物理和化学性质的溶剂。 直接测量温度相关力 羟丙基纤维素分子显示出几种新的特征， 温度有利生物聚合物自组装。 今年最重要的理论发展是 水氢键密度可能贡献的分析 带电基团间静电相互作用的涨落 被几个水分子隔开 根据最近的计算机 该理论预测振荡静电势 在标准的宏观模型中被解释。

This project combines theoretical modeling and laboratory measurements for determining the universal physical principles behind the organization and function of different macromolecular systems. The principal area of interest is that of proteins. Osmotic stress measurements at various solution conditions conducted this year have provided strong evidence that self-assembly of collagen molecules requires the formation of special hydrogen-bonded water bridges between opposing polar residues. The most likely sites of these bridges are two large, identical, histidine-containing sequences located near each end of the collagen molecule. Combined Raman and X-ray experiments have demonstrated that dehydration of reconstituted collagen fibers involves significant changes in interstitial water hydrogen-bond network; the changes are consistent with our theoretical model of hydration forces. In order to better understand features of interstitial water that are essential for collagen interaction and self-assembly, we have now begun measurements of forces between collagen triple helices in non-aqueous solvents having different physical and chemical properties. Direct measurements of temperature-dependent forces between hydroxypropylecellulose molecules have shown several new features of temperature-favored biopolymer self-assembly. The most significant theoretical development this year has been the analysis of possible contributions from water hydrogen-bond-density fluctuations to electrostatic interactions between charged groups separated by several water molecules. In agreement with recent computer simulations this theory predicts oscillating electrostatic potentials that are accounted for in standard macroscopic models.