STRUCTURAL STUDIES ON LIPOXYGENASES

脂加氧酶的结构研究

• 批准号: 8361694
• 负责人: MARCIA E. NEWCOMER
• 金额: $ 3.84万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361694
• 关键词: Address; Animals; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Carbon; Data; Eicosanoids; Enzymes; Funding; Grant; Hydrogen; Inflammatory; Leukotrienes; Life; Lipoxygenase; Modeling; Molecular; National Center for Research Resources; Phospholipase A2; Principal Investigator; Production; Protein Isoforms; Reaction; Regulation; Research; Research Infrastructure; Resources; Site; Source; Specificity; United States National Institutes of Health; base; cost; lipid mediator; mutant; peroxidation; prevent; programs; research study; structural biology; suicide inactivation

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 enzyme 5-lipoxygenase (5-LOX) initiates the synthesis of pro-inflammatory leukotrienes. These lipid mediators are synthesized from arachidonic acid (AA) released from the bilayer by the action of Ca2+-dependent phospholipase A2. 5-LOX activity is short-lived, and temporal control appears in part due to an intrinsic instability of the enzyme. This instability provides a mechanism for auto-regulation, preventing an over-production of pro-inflammatory leukotrienes. However, "programmed obsolescence" is not common to all lipoxygenases, and stable isoforms have been identified. We address two critical aspects of control of 5-LOX activity: (1) Product specificity The substrate for 5-LOX is the polyunsaturated eicosanoid arachidonic acid. The first step of the reaction is the abstraction of hydrogen from the central carbon of a pentadiene. AA has three pentadiene moieties (and six possible sites of peroxidation, each with either R- or S- chirality). Yet animal lipoxygenases generally produce a single, regio- and stereo- specific product. We will develop a model for 5-LOX specificity that is consistent with its product specificty. (2) Programmed obsolescence "Programmed obsolescence" in 5-LOX appears to have two components: structural instability and turnover-based suicide inhibition. Our data, including our stable mutant form of 5-LOX, suggest that features unique to 5-LOX result in a tenuously restrained C-terminus that contributes to 5-LOX instability. Experiments to define the molecular basis for non-turnover and turnover-based inactivation are proposed.

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。 酶5-脂氧酶（5-lox）启动了促炎白细胞的合成。这些脂质介质是通过Ca2+依赖性磷脂酶A2的作用从双层释放的花生四烯酸（AA）合成的。 5-lox活性是短暂的，时间控制部分是由于酶的内在不稳定。这种不稳定性提供了一种自动调节的机制，防止了促炎白细胞的过度生产。然而，“程序化过时”并不是所有脂氧酶的共同点，并且已经鉴定出稳定的同工型。我们解决了5-lox活性控制的两个关键方面：（1）产品特异性5-lox的底物是多不饱和的类固醇类蛛网膜酸。反应的第一步是从戊二烯的中央碳中氢气的抽象。 AA具有三个五烯部分（以及六个可能的过氧化位点，每个都有R-或S-手性）。然而，动物Lipoxygyass通常会产生单一的，区域和立体的产品。我们将为5-LOX特异性开发模型，该模型符合其产品的特殊性。 （2）5-LOX中编程的过时的“编程过时”似乎具有两个组成部分：结构不稳定性和基于营业额的自杀抑制。我们的数据，包括我们稳定的5-lox突变体形式，表明5-lox独有的特征会导致严格约束的C末端，从而导致5-lox不稳定性。提出了定义非转化和基于离职的灭活的分子基础的实验。