Thermodynamics of Protein-Protein Interactions

该项目的目标是开发预测蛋白质之间分子识别的能力。 分子识别由蛋白质-蛋白质相互作用的热力学决定。 这些热力学反过来又由蛋白质的结构决定，并且可以通过环境变量如pH和其他小配体的存在来调节。 丝氨酸蛋白酶与蛋白质抑制剂相互作用的热力学将通过等温滴定量热法进行研究，并与使用已证明成功预测蛋白质稳定性的基于经验的方法从晶体学或模型化结构计算的能量学进行比较。 此外，pH值对结合的影响的基础将进行研究，通过定点突变，旨在扰乱质子亲和力的活性位点组氨酸，位于蛋白质-蛋白质界面。 最后，结合磷酸盐的复合物将作为温度和pH值的函数进行研究。这项工作的目标是提供一个更好的理解蛋白质结构和结合能之间的关系。 这也将提高我们对蛋白质环境如何调节可电离基团的pKa的理解。 这些知识对于设计具有特异性分子识别和pH敏感性结合特性的蛋白质的能力至关重要。

The goal of this project is to develop the ability to predict molecular recognition between proteins. Molecular recognition is determined by the thermodynamics of protein-protein interactions. These thermodynamics, in turn, are determined by the structures of the proteins, and can be modulated by environmental variables such as pH and the presence of other small ligands. The thermodynamics of interaction of serine proteases with proteinaceous inhibitors will be studied by isothermal titration calorimetry and compared to the energetics calculated from the crystallographic or modeled structures using empirically based methods which have proven successful in predicting protein stability. Additionally, the basis of pH effects on the binding will be studied by making site-directed mutations aimed at perturbing the proton affinity of the active site histidine, located in the protein-protein interface. Finally, the binding of phosphate to the complex will be studied as a function of temperature and pH.The goal of the work is to provide a better understanding of the relationship between protein structure and binding energetics. It will also improve our understanding of how the protein environment can modulate the pKa of an ionizable group. Such knowledge is critical to the ability to design proteins with specific molecular recognition and pH sensitive binding properties.