NMR STUDIES OF THE MECHANISMS OF ACTION OF TRP REPRESSOR

拟议项目的目标是实现一个详细的， 对遗传调控的分子机制的精确理解， 在这一层面上，这一机制运作的具体变化 是可以预测和设计的。 预测和控制 基因调控机制功能的改变将具有 对治疗遗传疾病的能力产生深远的影响， 利用这些机制作为合理药物设计的目标，但现有的 知识尚不足以实现这些目标。 从E.选择大肠杆菌作为模型系统， 研究，因为它是一个最小和最简单的完整的 现有的监管体系。 从已知的结构开始 阻遏蛋白，有和没有激活剂L-色氨酸， 和三元DNA-阻遏物-L-trp复合物， 系统地研究每个结构元件（氨基）的作用， 酸残基）在（1）中保持与L-trp配体的特异性接触 和（2）与操纵基因DNA和（3）传递信号调节 结合位点之间的DNA结合。 为实现这些目标将 研究点突变和多重突变，已知这些突变会改变 系统的构象和动力学。 非常有希望的初步结果 已经获得了一些突变体，提供了明确的 未来研究的方向。 调查结果的相关性应允许 了解信令代码和监管的设计 设备.

The objective of the proposed project is to achieve a detailed and precise understanding of the molecular mechanism of genetic regulation, at a level at which specific changes in the operation of this mechanism could be predicted and engineered. The ability to predict and control modifications to the function of genetic regulatory mechanisms will have far reaching consequences to the ability to treat genetic diseases and to use the mechanisms as targets for rational drug design, but existing knowledge is as yet insufficient to reach these goals. The trp-repressor from E. coli was chosen as a model system for detailed study, because it is one of the smallest and simplest complete regulatory systems available today. Starting with the known structures of the repressor protein, with and without the activator L-tryptophan, and of the ternary DNA-repressor-L-trp complex, it is possible to systematically investigate the role of each structural element (amino acid residue) in (1) maintaining specific contacts with the L-trp ligand and (2) with the operator DNA and (3) transmitting the signal regulating DNA binding between the binding sites. This will be achieved by studying point and multiple mutations which are known to alter the conformation and dynamics of the system. Very promising initial results have already been obtained with some of the mutants, providing clear directions for future studies. Correlation of the findings should allow an understanding of the signaling code and the design of the regulatory apparatus.