DETERMINATION OF THE PSEUDO-ATOMIC STRUCTURE OF NUCLEAR PORE COMPLEX (NPC) COMPO

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目及 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 核孔复合物（NPC，约50 MDa）是大分子物质穿过核膜的唯一通道。孔在许多关键的细胞过程中起着关键作用，如转录，其许多组分与人类疾病如癌症有关。以前的工作提供了第一个描述的酵母NPC的大分子结构。这种结构定义了它的456个组成核孔蛋白（nup）蛋白的相对位置和接近度，基于来自实验数据的空间限制。进一步阐明NPC的进化起源和运输机制将需要更高分辨率的信息。为了帮助提高NPC结构的分辨率和精度，我们建议在SSRL获得小角X射线散射（SAXS）数据。我们正在准备一套单一的蛋白质，蛋白质结构域，和小NPC亚复合物样品的SAXS分析。我们将应用我们的集成建模平台（IMP）软件，将一组不同的实验数据，包括SAXS光谱，作为空间约束，以确定这些亚复合物和蛋白质的三维结构。我们特别关注两个亚复合物的组成部分，7-蛋白质Nup 84亚复合物和4-蛋白质Nup 170复合物，可获得补充的实验数据。我们已经使用了类似的协议，以映射人类Hsp 90的不同功能状态。

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 Nuclear Pore Complex (NPC, about 50 MDa) is the sole passageway for the transport of macromolecules across the nuclear envelope. The pore plays a key role in numerous critical cellular processes such as transcription, and many of its components are implicated in human diseases such as cancer. Previous work provided the first description of the macromolecular architecture of the yeast NPC. This structure defined the relative positions and proximities of its 456 constituent nucleoporin (nup) proteins, based on spatial restraints derived from experimental data. Further elucidation of the evolutionary origin and transport mechanism of the NPC will require higher resolution information. To help improve upon the resolution and accuracy of the NPC structure, we propose to obtain small angle x-ray scattering (SAXS) data at SSRL. We are preparing a set of single protein, protein domain, and small NPC subcomplex samples for SAXS analysis. We will apply our Integrated Modeling Platform (IMP) software to incorporate a diverse set of experimental data, including SAXS spectra, as spatial restraints, to determine the three dimensional structures of these subcomplexes and proteins. We are specifically focusing on components of two subcomplexes, the 7-protein Nup84 subcomplex, and the 4-protein Nup170 complex, for which complementary experimental data are available. We have already used a similar protocol, to map different functional states of human Hsp90.