STUDIES OF THE TRANSMEMBRANE SELENOPROTEIN K AND ITS ROLE IN OXIDATIVE DEFENSE

跨膜硒蛋白 K 及其氧化防御作用的研究

• 批准号: 8364948
• 负责人: Sharon Rozovsky
• 金额: $ 10.53万
• 依托单位: UNIVERSITY OF DELAWARE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8364948
• 关键词: Aerobic; Anti-Inflammatory Agents; Anti-inflammatory; Antioxidants; Antiviral Agents; Binding; Biochemical; Biological Assay; Cells; Centers of Research Excellence; Chemopreventive Agent; Electron Transport; Environment; Free Radicals; Funding; Goals; Grant; Health; Human; Indium; Life; Lipid Bilayers; Lipid Peroxidation; Lipids; Longevity; Membrane; Membrane Proteins; Metals; National Center for Research Resources; Oxidation-Reduction; Oxidative Stress; Oxygen; Peroxidases; Principal Investigator; Production; Proteins; Reaction; Reactive Oxygen Species; Research; Research Infrastructure; Resources; Role; Sampling; Selenium; Selenium Compounds; Selenocysteine; Signal Transduction; Source; Stress; Structure; Sulfur; Testing; United States National Institutes of Health; chemical property; cost; fluidity; in vivo; overexpression; oxidation; selenoprotein

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. Selenium is an essential element in all branches of life, where its strong nucleophilicity, redox activity, metal binding capacities, and low pKa are utilized to catalyze redox and electron transfer reactions. In human health, selenium compounds and selenoproteins contribute to chemopreventive, anti-inflammatory, and antiviral defense. This project focuses on elucidating the unknown structure and function of the selenium-containing membrane protein, selenoprotein K (SelK). SelK is a small (94 residues) protein with a single-pass transmembrane helix predicted at its N terminus, and a selenocysteine at its C terminus. It has been shown to reduce internal levels of reactive oxygen species and to protect cells against oxidative stress. Oxidative stress, caused by externally and internally generated reactive oxygen species (ROS), is an unavoidable corollary of aerobic life and is tightly connected to longevity. ROS tend to concentrate in the lipid bilayer where oxygen and other free radicals are more soluble. Not surprisingly, ROS are prone to modify both lipids and membrane proteins, with lipid peroxidation being the most common ROS-induced damage. Such modified lipids change the physico-chemical properties, e.g. fluidity and curvature stress of the lipid bilayer, and thus destabilize biomembranes. Due to the specialized cellular roles of selenoproteins, SelK's participation in anti-oxidant defense in vivo and SelK's membrane localization, we hypothesize that SelK is involved in protecting biomembranes against reactive carbonyl species generated by lipid oxidation. To facilitate its structural and biophysical characterization we are developing bacterial overexpression and purification strategies for both the native selenium and sulfur-substituted SelK. The oligomerization state of SelK and sample conditions for structural characterization will be evaluated. To identify the role of SelK in oxidative stress and signaling, we will use functional assays to test for its potential peroxidase activity. Our long-term goal is to delineate the biochemical role of SelK, the unique contribution of selenium to its reactivity, and SelK function in its native membrane environment.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 硒是生命各分支中必不可少的元素，其强亲核性、氧化还原活性、金属结合能力和低pKa可用于催化氧化还原和电子转移反应。在人类健康中，硒化合物和硒蛋白有助于化学预防、抗炎和抗病毒防御。该项目的重点是阐明含硒膜蛋白硒蛋白 K (SelK) 的未知结构和功能。 SelK 是一种小型（94 个残基）蛋白质，其 N 末端预计有单程跨膜螺旋，C 末端有硒代半胱氨酸。它已被证明可以降低活性氧的内部水平并保护细胞免受氧化应激。由外部和内部产生的活性氧 (ROS) 引起的氧化应激是有氧生活不可避免的必然结果，与长寿密切相关。 ROS 倾向于集中在脂质双层中，其中氧和其他自由基更容易溶解。毫不奇怪，ROS 很容易修饰脂质和膜蛋白，其中脂质过氧化是 ROS 引起的最常见的损伤。这种修饰的脂质改变了物理化学性质，例如脂质双层的流动性和曲率应力，从而使生物膜不稳定。由于硒蛋白的特殊细胞作用、SelK 参与体内抗氧化防御以及 SelK 的膜定位，我们假设 SelK 参与保护生物膜免受脂质氧化产生的反应性羰基物质的影响。 为了促进其结构和生物物理表征，我们正在开发天然硒和硫取代 SelK 的细菌过表达和纯化策略。将评估 SelK 的寡聚状态和结构表征的样品条件。为了确定 SelK 在氧化应激和信号传导中的作用，我们将使用功能测定来测试其潜在的过氧化物酶活性。我们的长期目标是描述 SelK 的生化作用、硒对其反应性的独特贡献以及 SelK 在其天然膜环境中的功能。