SOLUTION STRUCTURE OF THE SIGNAL RECOGNITION PARTICLE FROM T AQUATICUS: A SAXS

T AQUATICUS 信号识别粒子的解决方案结构：SAXS

• 批准号: 7598025
• 负责人: Robert M Stroud
• 金额: $ 0.3万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598025
• 关键词: Binding; Cell membrane; Charge; Complex; Computer Retrieval of Information on Scientific Projects Database; Endoplasmic Reticulum; Eubacterium; Funding; GTPase-Activating Proteins; Gel Chromatography; Grant; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Hydrolysis; Institution; Life; Membrane; Membrane Proteins; Modeling; Molecular; Molecular Conformation; Nucleotides; Pathway interactions; Peptide Signal Sequences; Protein Overexpression; Protein translocation; Proteins; RNA; Research; Research Personnel; Resolution; Resources; Ribosomes; Shapes; Signal Recognition Particle; Solutions; Source; Structure; Techniques; Thermus; Translating; United States National Institutes of Health; analytical ultracentrifugation; light scattering; receptor

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 signal recognition particle (SRP) and its membrane-associated receptor (SR) constitute an evolutionary conserved macromolecular ribonucleoproteic complex that catalyzes targeting of nascent secretory and membrane proteins to the protein translocation apparatus. The SRP is in charge of directing ribosomes which are currently translating proteins destined for either secretion or membrane integration to the endoplasmic reticulum or plasma membrane. The receptor is responsible for the targeting of the ribosome-nascent protein-SRP complex to the membrane translocation machinery. The components of the SRP pathway and the essential steps of the molecular mechanism of SRP-dependent protein targeting are conserved in all three kingdoms of life. The thermostable signal recognition particle from the eubacteria Thermus aquaticus (Taq) is a ribonucleic acid-protein complex composed of the SRP-RNA, which is 113 nucleotides long (35 kDa), and two proteins, the receptor subunit FtsY (33 kDal) and the RNA and signal sequence-binding subunit Ffh (48 kDa). In addition both proteins are structurally related GTPases and GTP-dependent GTPase-activating proteins (GAPs). The ribosome-nascent protein-SRP complex interaction with its receptor is also GTP dependent. GTP hydrolysis by the SRP-SR complex dissociates this complex, allowing a new round of targeting. All components of the Taq-SRP are overexpressed and soluble and have been extensively characterized by gel filtration, dynamic light scattering and analytical ultracentrifugation, in terms of homogeneity and stability. The aim of this biophysical study by SAXS is to charactize the shapes and the conformations of the Taq-SRP and its subcomponents in solution. Since the crystal structures of the isolated subunits are available, using SAXS techniques we wish to construct low-resolution models of the binary (FtsY/Ffh) and ternary (FtsY/Ffh/SRP-RNA) complexes whose structures are still unknown.

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。 信号识别颗粒（SRP）及其膜相关受体（SR）构成进化保守的大分子核糖核蛋白复合物，催化新生分泌蛋白和膜蛋白靶向蛋白质易位装置。 SRP 负责引导核糖体，核糖体目前正在翻译用于分泌或膜整合的蛋白质到内质网或质膜。 该受体负责将核糖体新生蛋白-SRP 复合物靶向膜易位机制。 SRP 途径的组成部分和 SRP 依赖性蛋白靶向的分子机制的基本步骤在所有三个生命王国中都是保守的。来自真细菌水生栖热菌 (Taq) 的耐热信号识别颗粒是一种核糖核酸-蛋白质复合物，由 113 个核苷酸长 (35 kDa) 的 SRP-RNA 和两种蛋白质组成，即受体亚基 FtsY (33 kDal) 以及 RNA 和信号序列结合亚基 Ffh (48 kDa)。此外，这两种蛋白都是结构相关的 GTP 酶和 GTP 依赖性 GTP 酶激活蛋白 (GAP)。核糖体新生蛋白-SRP 复合物与其受体的相互作用也是 GTP 依赖性的。 SRP-SR 复合物水解 GTP 会解离该复合物，从而实现新一轮的靶向。 Taq-SRP 的所有组分均过表达且可溶，并已通过凝胶过滤、动态光散射和分析超速离心在均质性和稳定性方面进行了广泛表征。 SAXS 进行的这项生物物理研究的目的是表征溶液中 Taq-SRP 及其子成分的形状和构象。由于分离亚基的晶体结构是可用的，我们希望使用 SAXS 技术构建结构仍未知的二元 (FtsY/Ffh) 和三元 (FtsY/Ffh/SRP-RNA) 复合物的低分辨率模型。