STRUCTURE DETERMINATION OF THE RNAP ALPHA SUBUNIT

长期目标是了解 RNA聚合酶的转录起始和延伸。阿尔法 亚基是E.杆菌它 启动功能酶自身的组装。它也是 在酶和它的外部调节器之间的桥梁， 转录激活因子，它也收缩DNA。由于 很难获得RNA聚合酶的高分辨率结构， 总的来说，以下方法是获得详细结构的更好方法 信息形成复合体。它决定了 通过X射线晶体学分析α亚基， 低分辨电子显微镜下复合物中的α亚基 RNA聚合酶的结构获得了低分辨率结构 由达斯特博士和他的同事在E. coli RNAP全酶（27 A 分辨率）和E. coli核心酶（12 A分辨率）。与此同时， 实验正在进行中，使用抗体标记和其他方法， 在低分辨率的密度中定位α亚基 结构结合X射线晶体学和电子显微镜 数据将为思考RNAP组装提供更多信息， 这比任何一种方法单独提供的功能都要好。

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.