Chalkophore-mediated copper homeostasis in Staphylococcus lugdunensis

路邓葡萄球菌中铜基团介导的铜稳态

• 批准号: 534312091
• 负责人: Professor Dr. Simon Heilbronner
• 金额: --
• 依托单位: Department of Biochemistry
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/534312091?language=en
• 关键词: Chalkophore; mediated; copper; homeostasis; Staphylococcus

Metal ions are needed as cofactors for many enzymes and are therefore essential for a functional metabolism. However, due to their redox potential, metal ions do also harbour intrinsic toxicity and cytosolic metal homeostasis needs strict control. Metal homeostasis is an important target for human innate immunity. Availability of trace metals such as iron (Fe) is actively limited within the host to reduce pathogen proliferation during infection. In contrast, a targeted increase of copper concentration within phagolysosomes kills bacteria. Bacteria produce several metallophores to improve metal acquisition. Best studied are iron-binding siderophores. However, isolated reports exist describing that in addition to iron, siderophores can bind copper. This can allow detoxification, as compound binding impacts redox characteristics. Additionally, it ensures sufficient Cu-ion supply for metabolic activity. However, the relevance of copper-binding metallophores (chalkophores) for pathogens in the context of colonisation and disease is insufficiently understood. We found that the pathogen S. lugdunensis produces the compound Ulbactin F, and found the molecule to be a chalkophore. The responsible genetic locus encodes biosynthesis systems as well as putative exporters and importers, strongly suggesting that the molecule is important for metal homeostasis. I suggest to characterize this system on the molecular level and to study its physiological relevance. I request funding for two PhD positions to study distinct topics using highly synergistic approaches. The first PhD student will investigate the relevance of Ulbactin F biosynthesis and membrane transport on metal homeostasis of S. lugdunensis. The student will perform elementary analysis of wild type and Ulbactin F deficient strains to confirm the role of the molecule on intracellular metal levels. Additionally, the student will investigate membrane transport of Ulbactin F. We identified an ABC-transporter of the energy coupling factor (ECF) type within the Ulbactin F locus. ECF-transporters are trace nutrient acquisition systems. We will study the Ulbactin F binding properties of the ECF-transporter on the molecular level. Additionally, we will use isogenic mutants and heterologous expression of the ECF-transporter to validate its role in Ulbactin F acquisition. The second PhD student will study the physiological relevance of Ulbactin F. The student will perform in vitro experiments to investigate whether Ulbactin F production provides a growth advantage under copper ion-limiting conditions or if the molecule provides resistance to copper ions. Additionally, the student will study metal dependent regulation of Ulbactin F biosynthesis and use ex vivo and in vivo infection models to investigate whether the molecule represents a virulence factor of S. lugdunensis. Altogether, I am convinced that the suggested experiments will give a complete picture of the biology of the chalkophore Ulbactin F.

金属离子是许多酶所需的辅因子，因此对功能性代谢至关重要。然而，由于它们的氧化还原电位，金属离子也具有内在毒性，细胞溶质金属稳态需要严格控制。金属稳态是人体天然免疫的重要靶点。微量金属如铁（Fe）的可用性在宿主内被主动限制以减少感染期间的病原体增殖。相反，吞噬溶酶体内铜浓度的有针对性的增加杀死细菌。细菌产生几种金属载体来改善金属的获得。研究得最好的是铁结合铁载体。然而，存在描述除了铁之外，铁载体可以结合铜的孤立报告。这可以允许解毒，因为化合物结合影响氧化还原特性。此外，它还确保了代谢活动所需的足够的铜离子供应。然而，铜结合的金属载体（白垩基）的病原体的背景下，殖民化和疾病的相关性是不够理解。 我们发现病原体S. lugdunensis产生化合物Ulbactin F，并发现该分子是一种白垩基。负责的基因位点编码生物合成系统以及推定的出口商和进口商，强烈表明该分子对金属稳态很重要。我建议在分子水平上描述该系统并研究其生理相关性。我请求资助两个博士职位，使用高度协同的方法研究不同的主题。第一位博士生将研究Ulbactin F生物合成和膜转运对S. lugdunensis。学生将对野生型和Ulbactin F缺陷菌株进行元素分析，以确认分子对细胞内金属水平的作用。此外，学生将研究Ulbactin F的膜转运。我们确定了一个ABC-转运蛋白的能量耦合因子（ECF）型内的Ulbactin F基因座。ECF转运蛋白是微量营养素获取系统。我们将在分子水平上研究ECF-转运体的Ulbactin F结合特性。此外，我们将使用ECF-转运蛋白的同基因突变体和异源表达来验证其在Ulbactin F获取中的作用。第二个博士生将研究Ulbactin F的生理相关性。学生将进行体外实验，以研究Ulbactin F生产是否在铜离子限制条件下提供生长优势，或者该分子是否对铜离子具有抗性。此外，学生还将研究金属对Ulbactin F生物合成的依赖性调节，并使用离体和体内感染模型来研究该分子是否代表S. lugdunensis。总之，我相信，建议的实验将给出一个完整的图片的生物学的白垩基Ulbactin F。