The mobile ferrous iron pool in Escherichia coli is bound to a phosphorylated sugar derivative

Böhnke, R.; Matzanke, Berthold F.

doi:10.1007/bf00143380

Cited by 45 publications

(27 citation statements)

References 47 publications

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“…Such a component has been observed in many bacterial systems. In E. coli, it was shown that this component is located in the cytoplasm and corresponds to an oligomeric ferrous sugar-phosphate complex (6). The second component represents a ferric high-spin species exhibiting Mössbauer parameters similar to those of a variety of bacterial ferritins.…”

Section: Resultsmentioning

confidence: 99%

Differential Role of Ferritins in Iron Metabolism and Virulence of the Plant-Pathogenic BacteriumErwinia chrysanthemi3937

et al. 2008

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During infection, the phytopathogenic enterobacterium Erwinia chrysanthemi has to cope with iron-limiting conditions and the production of reactive oxygen species by plant cells. Previous studies have shown that a tight control of the bacterial intracellular iron content is necessary for full virulence. The E. chrysanthemi genome possesses two loci that could be devoted to iron storage: the bfr gene, encoding a heme-containing bacterioferritin, and the ftnA gene, coding for a paradigmatic ferritin. To assess the role of these proteins in the physiology of this pathogen, we constructed ferritin-deficient mutants by reverse genetics. Unlike the bfr mutant, the ftnA mutant had increased sensitivity to iron deficiency and to redox stress conditions. Interestingly, the bfr ftnA mutant displayed an intermediate phenotype for sensitivity to these stresses. Whole-cell analysis by Mössbauer spectroscopy showed that the main iron storage protein is FtnA and that there is an increase in the ferrous iron/ferric iron ratio in the ftnA and bfr ftnA mutants. We found that ftnA gene expression is positively controlled by iron and the transcriptional repressor Fur via the small antisense RNA RyhB. bfr gene expression is induced at the stationary phase of growth. The S transcriptional factor is necessary for this control. Pathogenicity tests showed that FtnA and the Bfr contribute differentially to the virulence of E. chrysanthemi depending on the host, indicating the importance of a perfect control of iron homeostasis in this bacterial species during infection.

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Section: Resultsmentioning

confidence: 99%

Differential Role of Ferritins in Iron Metabolism and Virulence of the Plant-Pathogenic BacteriumErwinia chrysanthemi3937

et al. 2008

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“…The DNA-protecting Dps protein that is ubiquitous in prokaryotes also binds iron (29); however, this functional aspect seems to be more related to the prevention of ROS generation than to a particular role in iron storage (357). The binding component of the intermediary mobile Fe(II) pool in Escherichia coli was found to comprise mainly phosphorylated sugar derivatives containing pentose and/or uronic acid as the major fraction (25). The compound was termed ferrochelatin.…”

Section: ϫ18mentioning

confidence: 99%

Siderophore-Based Iron Acquisition and Pathogen Control

Miethke

Marahiel

2007

Microbiol Mol Biol Rev

1,440

1,302

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SUMMARY High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as “Trojan horse” toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.

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“…Magnetite accounted for only 22.2% (ϩFe) and 8.9% (ϪFe) of the intracellular iron pool of RU-1, confirming the reduced magnetite biomineralization in the fur mutant observed by TEM. In all samples, only a small relative contribution came from a ferrous iron high-spin, ferrochelatin-like iron species also found in many bacterial and fungal systems (11). However, while in the WT the ferrous iron high-spin metabolite contributed only 0.35% to the intracellular iron pool, in RU-1 this metabolite was increased to 2% (RU-1 ϩFe) and 1.6% (RU-1 ϪFe).…”

Section: Resultsmentioning

confidence: 86%

Deletion of a fur -Like Gene Affects Iron Homeostasis and Magnetosome Formation in Magnetospirillum gryphiswaldense

et al. 2010

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Magnetotactic bacteria synthesize specific organelles, the magnetosomes, which are membrane-enveloped crystals of the magnetic mineral magnetite (Fe 3 O 4 ). The biomineralization of magnetite involves the uptake and intracellular accumulation of large amounts of iron. However, it is not clear how iron uptake and biomineralization are regulated and balanced with the biochemical iron requirement and intracellular homeostasis. In this study, we identified and analyzed a homologue of the ferric uptake regulator Fur in Magnetospirillum gryphiswaldense, which was able to complement a fur mutant of Escherichia coli. A fur deletion mutant of M. gryphiswaldense biomineralized fewer and slightly smaller magnetite crystals than did the wild type. Although the total cellular iron accumulation of the mutant was decreased due to reduced magnetite biomineralization, it exhibited an increased level of free intracellular iron, which was bound mostly to a ferritin-like metabolite that was found significantly increased in Mössbauer spectra of the mutant. Compared to that of the wild type, growth of the fur mutant was impaired in the presence of paraquat and under aerobic conditions. Using a Fur titration assay and proteomic analysis, we identified constituents of the Fur regulon. Whereas the expression of most known magnetosome genes was unaffected in the fur mutant, we identified 14 proteins whose expression was altered between the mutant and the wild type, including five proteins whose genes constitute putative iron uptake systems. Our data demonstrate that Fur is a regulator involved in global iron homeostasis, which also affects magnetite biomineralization, probably by balancing the competing demands for biochemical iron supply and magnetite biomineralization.

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The mobile ferrous iron pool in Escherichia coli is bound to a phosphorylated sugar derivative

Cited by 45 publications

References 47 publications

Differential Role of Ferritins in Iron Metabolism and Virulence of the Plant-Pathogenic BacteriumErwinia chrysanthemi3937

Differential Role of Ferritins in Iron Metabolism and Virulence of the Plant-Pathogenic BacteriumErwinia chrysanthemi3937

Siderophore-Based Iron Acquisition and Pathogen Control

Deletion of a fur -Like Gene Affects Iron Homeostasis and Magnetosome Formation in Magnetospirillum gryphiswaldense

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