STRUCTURE/FUNCTION OF UBIQUITIN CONJUGATING ENZYMES

泛素结合酶的结构/功能

• 批准号: 2543686
• 负责人: VINCENT CHAU
• 金额: $ 15.3万
• 依托单位: PROSCRIPT, INC.
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2543686
• 关键词: Saccharomyces cerevisiae; X ray crystallography; enzymes; gene mutation; oligonucleotides; protein structure function; recombinant proteins; site directed mutagenesis; suppressor mutations; ubiquitin

The posttranslational attachment of ubiquitin to proteins is used in eukaryotes to target a broad range of proteins for selective degradation. Selective removal of proteins is required for a number of cellular processes and a requirement for ubiquitin has been shown for processes ranging from the determination of cell fate in division, differentiation, oncogenesis and senescence to more specific processes such as DNA repair, inflammatory response, signal transduction and the removal of abnormal proteins. Many of these processes are also under intense investigation because of their relevance in human diseases. Oncogenesis and the inflammatory responses are two examples. The specificity of protein ubiquitination is conferred by a family of related proteins known as ubiquitin conjugating-enzymes (Ubc). Members in this family interact with a distinct set of substrate-binding proteins (also known as E3), and it is these cascades of interaction between Ubc and E3 proteins that enable the pathway to target a broad range of proteins for degradation. Ubc proteins all share a common conserved domain of approximately 150-170 amino acid residues. The Class I enzymes are the smallest and are comprised entirely of this domain. This conserved domain in larger, multifunctional Ubc's can also function autonomously. Thus, there must be unique structural features embedded in the conserved domain of an individual Ubc protein that enable each enzyme to interact specifically with its own set of E3 proteins. Analyses of Ubc sequences and the three known crystal structures of Class I enzymes have led us to formulate a general model that predicts how similarity and differences in Ubc's are manifested structurally. Our long term goal is to determine how specific regions in Ubc proteins are utilized for its function. The specific aims for this research period is 1) to analyze the effect of mutations on the function of selected Ubc's in the yeast S. cerevisiae, with the intention of defining those regions that are responsible for Ubc interaction with E3, 2)to initiate studies toward determining the crystal structure of a Ubc4-E3 complex; 3) to define E3 proteins that function in the Ubc7-dependent pathway.

泛素与蛋白质的翻译后附着用于 真核生物靶向多种蛋白质进行选择性降解。 许多细胞需要选择性去除蛋白质 过程和已显示过程对泛素的要求 从决定细胞命运的分裂、分化、 肿瘤发生和衰老到更具体的过程，例如 DNA 修复， 炎症反应、信号转导和异常物质的清除 蛋白质。 其中许多流程也正在接受深入调查 因为它们与人类疾病相关。 肿瘤发生和 炎症反应是两个例子。 蛋白质泛素化的特异性是由一个家族赋予的 相关蛋白质称为泛素结合酶 (Ubc)。 成员于 该家族与一组独特的底物结合蛋白相互作用 （也称为 E3），正是 Ubc 和 E3 蛋白使该途径能够靶向广泛的蛋白质 降解。 Ubc 蛋白均具有大约 150-170 个共同的保守结构域 氨基酸残基。 I 类酶是最小的并且是 完全由该域组成。 这个保守域更大， 多功能 Ubc 还可以自主运行。 因此，必须有 嵌入在保守域中的独特结构特征 使每种酶能够特异性相互作用的单个 Ubc 蛋白 具有自己的一组 E3 蛋白。 Ubc序列分析及三者 I 类酶的已知晶体结构使我们制定了 预测 Ubc 的相似性和差异性的通用模型 表现在结构上。 我们的长期目标是确定具体如何 Ubc 蛋白中的区域被利用来发挥其功能。 具体目标 本研究期的任务是 1) 分析突变对 选定的 Ubc 在酿酒酵母中的功能，目的是 定义负责 Ubc 与 E3 交互的区域， 2) 启动确定 Ubc4-E3 晶体结构的研究 复杂的; 3) 定义在 Ubc7 依赖性中发挥作用的 E3 蛋白 途径。