STRUCTURE DETERMINATION OF THE RNAP ALPHA SUBUNIT

我们的长期目标是理解 RNA聚合酶的转录起始和延伸。阿尔法 亚基是来自大肠杆菌的RNA聚合酶的关键部分。它 启动功能性酶本身的组装。它还可以用作 酶与其外部调节因子之间的桥梁，如许多 转录激活剂，它也会收缩DNA。由于 获得RNA聚合酶高分辨结构的难度 总的来说，下面的方法是获得详细结构的更好方法 信息构成了这个综合体。那就是确定原子的结构 用X-射线结晶学方法确定α亚基的位置 低分辨电子显微镜观察复合体中的α亚基 RNA聚合酶的结构。获得了低分辨率的结构 由Darst博士和他的E.Coli RNAP全酶(27A)的同事 分辨率)和大肠杆菌核心酶(12A分辨率)。同时， 使用抗体标记和其他方法的实验正在进行中 在低分辨率的密度范围内定位Alpha子单元 结构。X射线结晶学和电子显微镜相结合 数据将提供更多有关RNAP组装和 功能，而不是任何一种方法单独提供的功能。

The long term goal is to understand the regulation mechanism of transcription initiation and elongation of RNA polymerase. The alpha subunit is a critical part of the RNA polymerase from E. coli. It initiates the assembly of the functional enzyme itself. It also serves as a bridge between the enzyme and its external regulators such as many transcription activators, and it contracts DNA as well. Due to the difficulty to obtain high resolution structure of RNA polymerase as a whole, the following approach is the bet way to gain detailed structure information form the complex. That is determining the atomic structure of the alpha subunit by x-ray crystallography and finding the location of alpha subunit in the complex from low resolution electron microscopy structure of RNA polymerase. Low resolution structures have been obtained by Dr. Darst and his co-workers of E. coli RNAP holoenzyme (27 A resolution) and E. coli core enzyme (12 A resolution). Concurrently, experiments are underway using antibody labeling and other methods to locate the alpha subunits within the density of the low-resolution structure. The combined X-ray crystallographic and electron microscopy data will provide more information for thinking about RNAP assembly and function than either method will provide alone.