CONFORMATIONAL CHANGES IN AN IMPORTANT E3 UBIQUITIN LIGASE COMPLEX

重要 E3 泛素连接酶复合物的构象变化

• 批准号: 8361306
• 负责人: ANDREW D MESECAR
• 金额: $ 0.59万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361306
• 关键词: Affect; Anabolism; Biophysics; Broccoli - dietary; Cells; Chemopreventive Agent; Complex; Cysteine; DNA Repair; Development; Dimensions; Enzymes; Funding; Future; Genetic Transcription; Glutathione; Grant; Homeostasis; Humulus; Inflammation; Mass Spectrum Analysis; Measures; Modification; NF-E2-related factor 2; National Center for Research Resources; Nuclear; Oxidation-Reduction; Principal Investigator; Radial; Regimen; Research; Research Infrastructure; Resources; Signal Transduction; Source; Structure; Sulforaphane; Ubiquitination; United States National Institutes of Health; base; cancer chemoprevention; cost; macromolecule; particle; protein complex; research study; small molecule; transcription factor; ubiquitin-protein ligase

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. Cancer chemoprevention is an exciting field of research focusing on small molecules from natural sources and how they affect our body in beneficial and cytoprotective ways. Several of these chemopreventive compounds, such as sulforaphane from broccoli and xanthohumol from hops, covalently modify a specific complex of macromolecules in the cell called the Cul3- based E3 ubiquitin ligase. This complex of proteins ubiquitinate a substrate protein, Nrf2, which is a major transcription factor regulating the levels of cytoprotective enzymes. When one of these compounds is introduced to cells, ubiquitination is shutdown through an unknown signaling mechanism. This leads to the nuclear accumulation of Nrf2, allowing for enhanced transcription of enzymes involved in redox homeostasis, glutathione biosynthesis, inflammation suppression, and DNA repair. Covalent adduction of the compounds to reactive cysteines within the Keap1 molecule has been observed by mass spectrometry. It is hypothesized that this covalent modification leads to the ubiquitination shutdown through an alteration in the complex's quaternary structure. This hypothesis can be readily explored using small angle scattering experiments, where the radius of gyration (Rg) and maximal linear dimension (Dmax) of the complex is measured before and after challenge with one of the chemopreventive compounds. If modification causes the complex to dissociate into smaller particles, then the Rg and Dmax will change accordingly. Understanding how these beneficial small molecules affect the structure of the Cul3-based E3 ubiquitin ligase complex will aid in the development of better, more potent chemopreventive regimens in the future.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 癌症化学预防是一个令人兴奋的研究领域，重点是自然来源的小分子，以及它们如何以有益和细胞保护的方式影响我们的身体。 这些化学预防化合物中的几种，例如来自西兰花的硫烷和啤酒花的xanthohumol，共价修改了该细胞中的特异性大分子，称为CUL3-基于Cul3-基于E3-基于E3-基于E3-基于E3-基于E3-基于E3-基于E3-基于E3-基于E3-泛素蛋白。 这种蛋白质的复合物泛素化底物蛋白NRF2，这是调节细胞保护酶水平的主要转录因子。当这些化合物之一引入细胞时，通过未知的信号传导机制关闭泛素化。这导致NRF2的核积累，从而增强了参与氧化还原稳态，谷胱甘肽生物合成，炎症抑制和DNA修复的酶的转录。通过质谱观察到了Keap1分子内反应性半胱氨酸的共价添加到反应性半胱氨酸中。假设这种共价修改通过复合物的第四纪结构的改变导致泛素化关闭。可以使用小角度散射实验来容易探索该假设，其中与一种化学预防化合物之一一起测量了复合物的回旋半径（RG）和最大线性尺寸（DMAX）。如果修饰使复合物分离为较小的颗粒，则RG和DMAX将相应地改变。了解这些有益的小分子如何影响基于CUL3的E3泛素连接酶复合物的结构将有助于发展更好，更有效的化学预防疗法。