Signal Propagation in Protein Allostery: Mechanism and Evolution

项目摘要/摘要 尽管它对生物学的重要性已经被认识到超过一个 世纪之交，变构的分子机制仍然是人们深入研究的主题。 在变构作用中，来自蛋白质中一个位点的信号被传递到第二个，通常是遥远的， 网站，以改变其功能。集合模型提供了一个框架，在该框架中 和/或结构变化可促进变构调节，即使在单个 蛋白。挑战在于破译哪些分子过程是信号的关键 变速箱。在这项工作中，我们将研究第二族的变构机理 生物素蛋白连接酶、大肠杆菌Bira蛋白。我们假设发生了比拉变构 通过多个回路的动态变化与残渣形成的直接耦合 网络。我们进一步假设，这种机制允许 变构在保留翻译后生物素的基本酶功能的同时 加法。这些假设将使用集成的遗传筛选、解决方案进行验证 生物物理测量、x射线结晶学和分子动力学模拟。 阐明变构在BIRA中的作用将提高我们对 变构机制，并可能被证明有助于开发选择性靶向的药物 用于创建基于生物素蛋白连接酶的特定微生物BPLS的技术工具。

Project Summary/Abstract Although its significance for biology has been recognized for more than a century, the molecular mechanism of allostery remains the subject of intense research. In allostery a signal from one site in a protein is transmitted to a second, often distant, site to alter its function. The ensemble model provides a framework in which dynamic and/or structural changes can contribute to allosteric regulation even within a single protein. The challenge lies in deciphering which molecular processes are critical to signal transmission. In this work we will investigate the allosteric mechanism in the Group II Biotin Protein Ligase, E.coli BirA protein. We hypothesize that BirA allostery occurs through direct coupling of dynamic changes in multiple loops to formation of residue networks. We further hypothesize that this mechanism allowed for the evolution of allostery while preserving an essential enzymatic function in post-translational biotin addition. These hypotheses will be tested using integrated genetic screening, solution biophysical measurements, x-ray crystallography, and molecular dynamics simulations. The elucidation of how allostery works in BirA will improve our general understanding of allosteric mechanisms and may prove useful for developing drugs that selectively target specific microbial BPLs and for creating Biotin Protein Ligase-based technology tools.