CRYSTALLOGRAPHIC STUDIES OF LARGE MACROMOLECULAR ASSEMBLIES

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 正在开展的项目包括涉及基因表达所有步骤的大分子组装体。 第一个是参与复制 DNA 的复制体组件，包括复制 DNA 聚合酶 III、DnaB 解旋酶和引物酶。 还正在研究与夹子复合并与 DNA 底物结合的夹子加载器的结构。 研究中的第二个组装是核糖体，特别是 50S 核糖体亚基，将扩展到包括蛋白质合成过程的各种状态下的整个 70S 核糖体。 使用 EF-Tu、EF-G 或释放因子结晶 70S 核糖体的尝试正在进行中。 此外，通过易位子分泌蛋白质过程中翻译 70S 核糖体的研究进展顺利。 第三种与基因表达无关的组装体是脂肪酸合酶，这是一种包含 8 种酶活性的 250 万分子量组装体，其晶体在 24 ID 时衍射分辨率为 3.8 ¿ 最后，参与转录的蛋白质的结构研究，包括 T7 RNA 聚合酶、脱辅基分解代谢基因激活蛋白和与启动子 DNA 结合的大肠杆菌 RNA 聚合酶全酶的起始中间复合物。 这些研究旨在了解单体和多亚基酶中的转录起始及其调节。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The projects being pursued include large macromolecular assemblies that are involved in all steps of gene expression. The first of these are components of the replisome involved in copying DNA, including the replicating DNA polymerase III, DnaB helicase and primase. Also being pursued is the structure of the clamp loader complexed with the clamp and bound to a DNA substrate. The second assembly under study is the ribosome, specifically the 50S ribosomal subunit, is to be extended to include the entire 70S ribosome in various states of the protein synthesis process. Attempts to crystallize the 70S ribosome with EF-Tu, or EF-G, or release factors are underway. Further, studies of the translating 70S ribosome in the process of secreting protein through a translocon are well along. A third assembly not related to gene expression is that of fatty acid synthase, a 2.5 million molecular weight assembly containing 8 enzyme activities, whose crystals diffract to 3.8 ¿ resolution at 24 ID. Finally, structural studies of proteins involved in transcription including initiation intermediate complexes of T7 RNA polymerase, apo-catabolite gene activator protein and E. coli RNA polymerase holoenzyme bound to a promoter DNA. These are being pursued to understand transcription initiation and its regulation in a monomeric and multisubunit enzyme.