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Bacterial anaerobic iron homeostasis

细菌厌氧铁稳态

基本信息

批准号：
9269104
负责人：
PATRICIA J KILEY
金额：
$ 29.55万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-01 至 2019-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9269104
关键词：
Aerobic Affect Affinity Anabolism Anaerobic Bacteria Anaerobiosis Bacteria Binding Binding Sites Biochemical Biochemistry Biological Assay Biological Models Biology Cells Complex DNA DNA Binding DNA-Binding Proteins Data Disease Environment Escherichia coli Escherichia coli K12 Funding Gene Expression Profile Gene Targeting Genes Genetic Genetic Transcription Genomics Goals Growth Heme Homeostasis Iron Laboratories Lead Ligation Link Measures Metals Microbe Microbiology Mutagenesis Nutrient Organism Oxidative Stress Oxygen Pathogenesis Pathogenicity Pathway interactions Positioning Attribute Principal Investigator Process Property Proteins Proteome Race Reaction Regulation Regulon Research Resources Role SECTM1 gene Site Specificity Stress Structure Sulfur Sum Symbiosis Systemic infection Testing Urinary tract infection Uropathogenic E. coli Virulence antimicrobial arm clinically relevant cofactor experience experimental study fitness in vitro Assay insight iron metabolism microbial novel pathogen programs promoter public health relevance response transcription factor

项目摘要

DESCRIPTION (provided by applicant): Iron is an essential nutrient for nearly all organisms because it serves as a co-factor for many proteins, often in the form of iron, heme or iron-sulfur (Fe-S) clusters. Yet iron is often scarce in the environment placing its acquisition and usage under control of some of the most highly regulated pathways in biology. We are studying two key regulators of iron metabolism in the facultative anaerobe Escherichia coli, IscR and Fur. We have found that the activity and genes that are transcribed by IscR and Fur change significantly under anaerobic conditions. Thus, this project seeks to understand how this change occurs and how it impacts the utilization of iron under anaerobic conditions. Our first goal is to understand how activity of Fur, the global regulator of iron homeostasis in this and other bacteria, is regulated under anaerobic conditions. We will determine if an increase in free iron under anaerobic conditions can explain the increased activity of Fur at select weak affinity promoters in the absence of oxygen. We discovered that IscR is a novel DNA-binding protein that recognizes different sequence motifs in its apo- and [2Fe-2S]-bound forms. A second goal of this proposal is to define the biochemical and structural properties of IscR that allow metal binding to alter its DNA-binding specificity under anaerobic conditions. In this funding period, we will extend our studies of Fur and IscR from the well-studied K12 laboratory E. coli strain to the clinically relevant uropathogenic E. coli CFT073. Uropathogenic E.coli is a major cause of urinary tract infections and studies in model systems have linked both Fur and IscR to pathogenesis by this strain. Our results will provide important new insight as to how function of Fur and IscR are altered under anaerobic conditions. In addition, understanding how the activity of these regulators are coordinated to control iron and Fe-S homeostasis will allow us to develop new strategies to control the growth of commensal and pathogenic microbes in the anaerobic environment of the host.

说明(申请人提供)：铁是几乎所有生物体的必需营养素，因为它是许多蛋白质的辅助因子，通常以铁、血红素或铁-硫(铁-S)簇的形式存在。然而，铁在环境中往往是稀缺的，这使得它的获取和使用受到生物学中一些最严格监管的途径的控制。我们正在研究兼性厌氧菌大肠杆菌中铁代谢的两个关键调节因子，ISCR和Fur。我们发现，在厌氧条件下，ISCR和Fur转录的活性和基因发生了显着变化。因此，该项目试图了解这种变化是如何发生的，以及它如何影响厌氧条件下铁的利用。我们的第一个目标是了解毛皮的活性，它是这种细菌和其他细菌中铁稳态的全球调节者，在厌氧条件下是如何调节的。我们将确定厌氧条件下游离铁的增加是否可以解释在无氧条件下Fur在选定的弱亲和力启动子上活性增加的原因。我们发现ISCR是一种新的DNA结合蛋白，它以apo和[2Fe-2S]结合的形式识别不同的序列基序。这项建议的第二个目标是定义ISCR的生化和结构属性，这些属性允许金属结合在厌氧条件下改变其DNA结合特异性。在此资助期内，我们将把我们对毛皮和ISCR的研究从研究良好的K12实验室大肠杆菌菌株扩展到临床相关的尿路致病大肠杆菌CFT073。尿路致病性大肠杆菌是尿路感染的主要原因，模型系统中的研究已将毛皮和ISCR与该菌株的发病机制联系起来。我们的结果将为了解在厌氧条件下毛皮和Iscr的功能如何变化提供重要的新见解。此外，了解这些调节因子的活性是如何协调控制铁和铁-S的动态平衡的，将使我们能够制定新的策略来控制宿主厌氧环境中的共生微生物和病原微生物的生长。