Gene Regulation by Oxidative Stress in Bacillus subtilis

枯草芽孢杆菌中氧化应激的基因调控

• 批准号: 0640616
• 负责人: John Helmann
• 金额: --
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0640616&HistoricalAwards=false
• 关键词: Gene; Regulation; Oxidative; Stress; Bacillus

This project addresses the biological roles and mechanisms of two bacterial regulatory proteins that respond to reactive oxygen species: Bacillus subtilis PerR and OhrR. The peroxide regulon (PerR) repressor is a member of the Fur (ferric uptake regulator) family of metal-dependent repressor proteins. PerR functions as a sensor of peroxide stress by reacting with hydrogen peroxide to generate hydroxyl radical, which modifies histidine residues that coordinate the bound Fe2+ cofactor. The resulting oxidized protein is inactive for DNA-binding. The OhrR protein contains a highly reactive cysteine residue that reacts with organic peroxides to generate a cysteine-sulfenic acid that then reacts with low molecular mass thiols to generate mixed-disulfides. Oxidized OhrR also forms a sulfenyl-amide derivative. These protein modifications inactivate the repressor leading to expression of organic hydroperoxide resistance. This project addresses the detailed mechanisms by which protein oxidation regulates the activity of these two proteins. This research will determine whether oxidized PerR is degraded, or the subject of a novel protein repair pathway. The effects of protein oxidation on OhrR will be investigated, and proteins that contribute to reactivation of OhrR will be defined. Related regulatory proteins are present in diverse bacteria, including important plant and animal pathogens where they function to regulate genes important for virulence. This research will address fundamental aspects of protein chemistry and oxidation. Protein oxidation is important in the life of all cells and is thought to contribute to ageing and numerous age-related diseases. The project will train students at all levels in genetic and protein chemistry techniques.

本项目研究了枯草芽孢杆菌PerR和OhrR两种对活性氧有反应的细菌调节蛋白的生物学作用和机制。过氧化物调节子（PerR）阻遏物是金属依赖性阻遏蛋白的Fur（铁摄取调节剂）家族的成员。PerR通过与过氧化氢反应产生羟基自由基，其修饰与结合的Fe 2+辅因子配位的组氨酸残基，作为过氧化物应激的传感器。所得氧化蛋白对DNA结合无活性。OhrR蛋白含有高度反应性的半胱氨酸残基，其与有机过氧化物反应生成半胱氨酸-次磺酸，然后与低分子量硫醇反应生成混合二硫化物。氧化的OhrR还形成亚磺酰基-酰胺衍生物。这些蛋白质修饰使阻遏物失活，导致有机氢过氧化物抗性的表达。该项目涉及蛋白质氧化调节这两种蛋白质活性的详细机制。这项研究将确定氧化PerR是否被降解，或者是一种新的蛋白质修复途径的主题。将研究蛋白质氧化对OhrR的影响，并确定有助于OhrR再激活的蛋白质。相关的调节蛋白存在于不同的细菌中，包括重要的植物和动物病原体，它们的功能是调节对毒力重要的基因。这项研究将解决蛋白质化学和氧化的基本方面。蛋白质氧化在所有细胞的生命中都很重要，被认为是导致衰老和许多与年龄有关的疾病的原因。该项目将对各级学生进行遗传和蛋白质化学技术方面的培训。