MOLECULAR MODELLING OF SOLVATION OF (PRO PRO GLY)10

我们调查了导致中国经济稳定的因素。 (Pro-Pro-Gly)10三螺旋构象的水溶液 [(Ppg)10]，这是对胶原蛋白三元组某些特征的简化模拟 螺旋。对稳定这种分子的因素的了解可能会 为智能聚合物和生物材料的设计做出贡献。 这种多肽形成一种类似于 胶原蛋白。然而，与胶原蛋白不同的是，它没有羟基脯氨酸。 形成链间或链内桥联氢键的残基 涉及被束缚的水域。然而，我们已经构建了一个模型 在(PPG)10中形成桥式氢键的束缚水 在每个结合水和一对不同的主链上的羰基之间 多肽链。这些水域被认为是受约束的，而不是 大量溶剂化的水，因为它们在空间上受到限制 只有流动性有限的水域才能进入的区域 不是用散装溶剂。我们还表明，这些因素的作用 结构稳定中的空间拥挤约束水 定性地解释了更大的稳定性和更高的熔点 的(PPG)10在重水中比在水中更容易发生这种情况 氢键中重原子间距离的变化 D2O相对于结合的H2O，这允许结构采用 几何构型对脯氨酸间的范德瓦尔斯更有利 相互作用，同时仍保持最佳氢键 几何图形。MidasPlus与加州大学旧金山分校的计算机图形学设施 实验室已用于图形建模和可视化 起始制备(PPG)10的分子几何构型 理论计算的一致性，用于监测 结构，并用于为 出版物和海报展示。

We have investigated the factors contributing to the stability in aqueous solution of the triple-helical conformation of (Pro-Pro-Gly)10 [(PPG)10], a simplified mimic of some features of the collagen triple helix. An understanding of the factors stabilizing this molecule may contribute to the design of intelligent polymers and biomaterials. This polypeptide forms a triple-stranded conformation similar to that of collagen. Unlike collagen, however, it has no hydroxyproline residues to form inter- or intra-chain bridging hydrogen bonds involving bound waters. However, we have constructed a model for bound waters in (PPG)10, in which bridging hydrogen bonds are formed between each bound water and a pair of backbone carbonyls on different polypeptide chains. These waters are considered bound, rather than waters of bulk solvation, because they are in sterically restricted regions which can only be accessed by waters with limited mobility and not by bulk solvent. We have also shown that the role of these sterically crowded bound waters in structure stabilization qualitatively explains the greater stability and higher melting point of (PPG)10 in deuterium oxide than in water This occurs due to slight changes in the inter-heavy atom distances in hydrogen bonds to bound D2O relative to bound H2O, which allow the structure to adopt a geometry somewhat more favorable for inter-proline van der Waals interactions while still maintaining optimal hydrogen-bonding geometry. MidasPlus and the facilities of the UCSF Computer Graphics Laboratory have been used for graphical modeling and visualization of the molecular geometry, for preparing (PPG)10 in the starting conformation for the theoretical calculations, for monitoring the structures after these calculations, and for preparing images for publication and poster presentation.