Heme as an iron source in Sinorhizobium meliloti

血红素作为苜蓿中华根瘤菌的铁源

• 批准号: 7263162
• 负责人: MARK R O'BRIAN
• 金额: $ 3.82万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7263162
• 关键词: Heme; iron; source; Sinorhizobium; meliloti

DESCRIPTION (provided by applicant): In addition to its many cellular functions, heme is also a source of nutritional iron for many bacteria. The acquisition and metabolism of heme is essential for virulence in bacterial pathogens of animals, but this system has only been defined in relatively few genera. It was shown recently that S. meliloti uses heme as a nutritional iron source in Sinorhizobium meliloti and related species. The ?-proteobacterial group to which S. meliloti belongs includes bacteria that form intracellular or close associations with higher eukaryotes in either a pathogenic or symbiotic context. Preliminary evidence suggests that genes involved in heme transport and metabolism in symbiotic S. meliloti have homologs in related animal pathogens. The broad objective of the proposed work is to characterize the heme utilization system in S. meliloti as an experimentally tractable model for the ?-proteobacteria, and to identify common molecular themes in pathogenic and symbiotic interactions with higher eukaryotes. The ShmR protein is a putative heme receptor that was identified as an outer membrane protein that binds heme, and is expressed in an iron-dependent manner. Evidence indicates that shmR is transcriptionally controlled by a heretofore unidentified regulatory system. ShmR homologs are found in taxonomically-related pathogens. Two specific aims are proposed to address iron-dependent control of heme transport. 1) Identify the cis-acting element within the shmR promoter that mediates control by iron. 2) Identify the regulatory protein that mediates iron control of the shmR gene. Control of shmR by iron is not mediated by the two known regulators, Irr or Fur. Identification of the iron-responsive cis-acting element within the shmR promoter gives us the means to identify the cognate regulator protein. This research will be done primarily in Montevideo, Uruguay at the Instituto de Investigaciones Bioldgicas Clemente Estable in collaboration with Elena Fabiano as an extension of NIH grant R01GM067966. The gross national income per capita of Uruguay is $3,790 according to the World Bank classification system.

描述（由申请人提供）：血红素除了具有许多细胞功能外，也是许多细菌的营养铁的来源。血红素的获取和代谢对动物细菌性病原体的毒力至关重要，但这一系统只在相对较少的属中被定义。近年来研究表明，墨氏Sinorhizobium meliloti及其近缘种利用血红素作为营养铁源。的吗?S. meliloti所属的变形菌群包括在致病或共生环境中与高级真核生物形成细胞内或密切关联的细菌。初步证据表明，共生体S. meliloti中参与血红素运输和代谢的基因在相关动物病原体中有同源物。所提出的工作的主要目的是表征黄芪的血红素利用系统作为一个实验可处理的模型？-变形菌，并确定与高等真核生物病原和共生相互作用的共同分子主题。ShmR蛋白是一种假定的血红素受体，被鉴定为结合血红素的外膜蛋白，并以铁依赖的方式表达。有证据表明，shmR是由一个迄今尚未确定的调控系统转录控制的。在分类相关的病原体中发现了ShmR同源物。提出了两个具体的目标，以解决铁依赖控制血红素运输。1)确定shmR启动子中介导铁调控的顺式作用元件。2)鉴定介导铁调控shmR基因的调控蛋白。铁对shmR的控制不是由两个已知的调节因子Irr或Fur介导的。鉴定shmR启动子中的铁反应顺式作用元件为我们鉴定同源调节蛋白提供了手段。这项研究将主要在乌拉圭蒙得维的亚的Instituto de Investigaciones Bioldgicas Clemente Estable与Elena Fabiano合作进行，作为NIH拨款R01GM067966的延伸。根据世界银行的分类系统，乌拉圭的人均国民总收入为3790美元。