Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, United States.
Biochemistry. 2021 Nov 9;60(44):3277-3291. doi: 10.1021/acs.biochem.1c00586. Epub 2021 Oct 20.
Iron is an essential nutrient for virtually every living organism, especially pathogenic prokaryotes. Despite its importance, however, both the acquisition and the export of this element require dedicated pathways that are dependent on oxidation state. Due to its solubility and kinetic lability, reduced ferrous iron (Fe) is useful to bacteria for import, chaperoning, and efflux. Once imported, ferrous iron may be loaded into apo and nascent enzymes and even sequestered into storage proteins under certain conditions. However, excess labile ferrous iron can impart toxicity as it may spuriously catalyze Fenton chemistry, thereby generating reactive oxygen species and leading to cellular damage. In response, it is becoming increasingly evident that bacteria have evolved Fe efflux pumps to deal with conditions of ferrous iron excess and to prevent intracellular oxidative stress. In this work, we highlight recent structural and mechanistic advancements in our understanding of prokaryotic ferrous iron import and export systems, with a focus on the connection of these essential transport systems to pathogenesis. Given the connection of these pathways to the virulence of many increasingly antibiotic resistant bacterial strains, a greater understanding of the mechanistic details of ferrous iron cycling in pathogens could illuminate new pathways for future therapeutic developments.
铁是几乎所有生物体的必需营养物质,特别是致病原核生物。然而,尽管它很重要,但这种元素的获取和输出都需要专门的途径,这些途径依赖于氧化态。由于其溶解度和动力学不稳定性,还原态二价铁 (Fe) 对细菌的导入、伴侣和外排很有用。一旦被导入,二价铁可能被加载到脱辅基和新生酶中,甚至在某些条件下被隔离到储存蛋白中。然而,过多的不稳定二价铁可能会产生毒性,因为它可能会错误地催化芬顿化学,从而产生活性氧物种并导致细胞损伤。因此,越来越明显的是,细菌已经进化出铁外排泵来应对过量的二价铁条件,并防止细胞内氧化应激。在这项工作中,我们强调了最近在理解原核生物二价铁输入和输出系统方面的结构和机制方面的进展,重点是这些基本运输系统与发病机制的联系。鉴于这些途径与许多抗生素耐药性细菌菌株的毒力有关,对病原体中二价铁循环的机制细节有更深入的了解,可能会为未来的治疗发展开辟新的途径。