Bacterial Proteins Containing Novel Iron Sites

含有新铁位点的细菌蛋白质

• 批准号: 6325573
• 负责人: DONALD M. KURTZ
• 金额: $ 25.34万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6325573
• 关键词: Desulfovibrio; X ray crystallography; bacterial proteins; circular magnetic dichroism; enzyme activity; hemerythrin; hydrogen peroxide; iron; metalloproteins; molecular cloning; northern blottings; nucleic acid sequence; oxidative stress; protein engineering; protein structure function; site directed mutagenesis; stop flow technique; structural biology; western blottings

DESCRIPTION: (provided by applicant) The overall goal of this research is to determine the roles of two types of diiron-oxo proteins, ruberythrin (Rbr) and hemerythrin (Hr) homologs in the oxidative stress response of the anaerobic, sulfate-reducing bacterium, Desulfovibrio vulgaris. A comprehensive set of in vitro and in vivo experiments is proposed in order to provide the framework for understanding the roles of these proteins in the oxidative stress response. A detailed molecular characterization, including an X-ray crystal structure, of the reactive form of Rbr is proposed. Hydrogen peroxide is implicated as the substrate for Rbr. Therefore, measurements of the kinetics of oxidation of Rbr by hydrogen peroxide using stopped-flow spectrophotometry are proposed. Characterization of the ability of Rbr to function as the terminal component of a peroxidase upon combination with one or more of the ancillary proteins is also proposed. The gene for a proposed regulator of the oxidative stress response, Fur, will be probed by deletion of the gene encoding Fur in the D. vulgaris chromosome and identification of the proteins whose expression is altered in this Fur-deletion strain. Hrs have heretofore been found only in marine invertebrates, in which it functions as an oxygen uptake and storage protein. We recently discovered Hr homologs in D. vulgaris. One of these Hr homologs forms a domain of a larger protein whose role is to sense small molecules in its environment and to initiate a chemo tactic response in D. vulgaris. We propose that this chemotaxis protein, called DcrH, senses oxygen, and causes the bacteria to swim towards lower oxygen concentrations. This anaerotactic response will be tested in a dcrH deletion strain. DcrH is the first characterized Hr homolog in any microorganism. An increasing number of Rbr and Hr homologs are being discovered in infectious anaerobic microorganisms. Therefore, these proposed studies would form the basis for understanding oxidative stress not only in D. vulgaris, but also in a diverse range of anaerobic microorganisms, several of which affect human health.

描述：（由申请人提供）这项研究的总体目标是 确定两种类型的二氧氧蛋白的作用，Ruberythrin（RBR）和 在厌氧的氧化应激反应中，hegerthrin（HR）同源物， 硫酸盐还原细菌，desulfovibrio dulgaris。一组全面 提出了体外和体内实验，以便为 了解这些蛋白质在氧化应激反应中的作用。一个 详细的分子表征，包括X射线晶体结构 提出了RBR的反应性形式。过氧化氢与 RBR的底物。因此，测量RBR氧化动力学 通过使用停止流分光光度准好测量法进行过氧化氢。 RBR功能作为终端成分的能力表征 与一种或多种辅助蛋白结合使用过氧化物酶是 也提出了。氧化应激调节剂的基因 通过缺失编码D的基因。 染色体和表达表达的蛋白质的鉴定 在这种毛皮缺失菌株中发生了变化。迄今仅发现HRS 海洋无脊椎动物，其中它充当氧气和储存 蛋白质。我们最近在D. vulgaris中发现了HR同源物。其中之一 同源物构成较大蛋白质的领域，该蛋白的作用是很小 分子在其环境中，并在D中启动化学战术反应。 寻常。我们提出，这种称为DCRH的趋化蛋白感觉氧气， 并导致细菌向较低的氧气浓度游泳。这 Anaerotactic响应将在DCRH缺失菌株中进行测试。 DCRH是 首先是任何微生物中的HR同源物。越来越多的 RBR和HR同源物在感染性厌氧中发现 微生物。因此，这些提出的研究将构成 不仅在D. d. pulgaris中了解氧化应激，而且了解多样 厌氧微生物范围，其中几种影响人类健康。