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

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 核孔复合体(NPC，约50 mda)是大分子跨核膜运输的唯一通道。Thre孔在许多关键的细胞过程中起着关键作用，如转录，它的许多成分与人类疾病有关，如癌症。先前的工作首次描述了酵母NPC的大分子结构。根据来自实验数据的空间限制，这种结构定义了其456个组成核孔蛋白(NUP)蛋白质的相对位置和邻近程度。进一步阐明鼻咽癌的进化起源和运输机制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。我们正在准备一套用于SAXS分析的单一蛋白质、蛋白结构域和小的NPC亚复合体样本。我们将应用我们的集成建模平台(IMP)软件来整合一组不同的实验数据，包括SAXS光谱，作为空间约束，以确定这些亚复合体和蛋白质的结构。我们特别关注两个亚复合体的成分，7-蛋白质Nup84亚复合体和4-蛋白质Nup170复合体，它们都有补充的实验数据。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The Nuclear Pore Complex (NPC, about 50 MDa) is the sole passageway for the transport of macromolecules across the nuclear envelope. Thre 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 to 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 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.