Novel Responses to Oxygen by Anaerobic Microorganisms

厌氧微生物对氧气的新反应

• 批准号: 6918702
• 负责人: Michael W. Adams
• 金额: $ 27.6万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6918702
• 关键词: NAD(P)H dehydrogenase; Raman spectrometry; X ray crystallography; active sites; aerobiosis; anaerobic bacteria; anaerobiosis; catalyst; circular magnetic dichroism; electron nuclear double resonance spectroscopy; electron spin resonance spectroscopy; enzyme activity; enzyme complex; enzyme mechanism; free radical oxygen; functional /structural genomics; hydrogen peroxide; infrared spectrometry; iron sulfur protein; microarray technology; oxidative stress; oxidoreductase; protein structure function; respiratory burst oxidase; stress proteins; superoxides

DESCRIPTION (provided by applicant): By definition, aerobic organisms, both prokaryotic and eukaryotic, require molecular oxygen for energy conservation. This is a mixed blessing, however, as extremely reactive oxygen derivatives are produced during normal metabolism that can damage all cellular components. These so-called reactive oxygen species (ROS) have been implicated in a wide variety of chronic and infectious human diseases, including cancer, Alzheimer's disease, arthritis and AIDS, yet ROS are also used as a defense system against pathogens and in signal transduction pathways. Understanding the responses of microbes to oxygen has direct ramifications for the treatment of diseases caused by anaerobic pathogens. In 1999 we proposed that anaerobes have a novel response to ROS in which a non-heme iron protein termed superoxide reductase (SOR) played a key role. SOR was characterized from the hyperthermophilic anaerobe, Pyrococcus furiosus, and over the prior funding period it has been established using structural and spectroscopic approaches that SOR is uniquely suited to catalyze superoxide reduction. Using DNA microarrays to all 2065 ORFs in the complete P. furiosus genome, it was shown that the genes encoding SOR and related proteins are all expressed at significant levels in the absence of any oxidative shock. P. furiosus is therefore continuously 'armed' and ready to deal with ROS exposure. This is a first line of defense, however, as DNA microarray analyses show that the complete response to oxidative stress requires the induction of a large number of novel proteins (encoded by conserved/hypothetical genes), some of which are also induced by growth at sub-optimal temperatures. In the proposed research, the novel stress-regulated proteins, together with SOR and related reductases and oxidases, will be characterized with respect to their regulation, multiprotein complex formation, and catalytic functions using immunological, biochemical and structural analyses. A variety of complementary spectroscopic techniques, including EPR, ENDOR, MCD, resonance Raman, FTIR and X-ray absorption, will be utilized to probe the catalytic function of specific members of the stress-related pathways, with particular emphasis on SOR. The results will provide completely new insights into the stress responses of anaerobes, and provide strategies for determining the function of uncharacterized hypothetic algenes that typically account for half of a microbial genome.

描述（由申请人提供）：根据定义，好氧生物（原核生物和真核生物）需要分子氧来保存能量。然而，这是一个喜忧参半的情况，因为在正常代谢过程中会产生极端活性氧衍生物，这些衍生物会破坏所有细胞成分。这些所谓的活性氧物质（ROS）与多种慢性和感染性人类疾病有关，包括癌症、阿尔茨海默病、关节炎和艾滋病，但ROS也用作抵抗病原体的防御系统和信号转导途径。了解微生物对氧气的反应对治疗由厌氧病原体引起的疾病有直接的影响。在1999年，我们提出了厌氧微生物有一个新的反应活性氧，其中非血红素铁蛋白称为超氧化物还原酶（SOR）发挥了关键作用。SOR的特点是从超嗜热厌氧菌，激烈的火球菌，并在先前的资助期间，它已被确定使用结构和光谱方法，SOR是唯一适合于催化超氧化物还原。使用DNA微阵列对完整的P. furiosus基因组中的所有2065个ORF进行分析，结果表明，编码SOR和相关蛋白的基因在没有任何氧化休克的情况下都以显著水平表达。因此，激烈疟原虫不断地“武装”并准备好应对ROS暴露。然而，这是第一道防线，因为DNA微阵列分析表明，对氧化应激的完全反应需要诱导大量新蛋白质（由保守/假设基因编码），其中一些也是由次优温度下的生长诱导的。在拟议的研究中，新的压力调节蛋白，与SOR和相关的还原酶和氧化酶，将其特征在于与他们的监管，多蛋白复合物的形成，和催化功能，使用免疫学，生物化学和结构分析。各种互补的光谱技术，包括EPR，ENDOR，MCD，共振拉曼，FTIR和X-射线吸收，将被用来探测的催化功能的特定成员的应力相关的途径，特别强调SOR。这些结果将为厌氧菌的应激反应提供全新的见解，并为确定通常占微生物基因组一半的未表征的假设algenes的功能提供策略。