Kinetic Study of the Oxidation of Catechol by Aqueous Copper(II)

Kamau, Patrick; Jordan, R. B.

doi:10.1021/ic010978c

Cited by 45 publications

(37 citation statements)

References 28 publications

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“…Recently it was demonstrated that enterobactin is a substrate of CueO in vitro (16). Copper in combination with the catecholate siderophore is much more toxic than copper alone because enterobactin and other catecholates can act as a Cu(II) reductants (15,18). We showed that CueO oxidized the siderophore enterobactin and its precursor 2,3-dihydroxybenzoic acid and thus protected E. coli cells against copper-induced killing.…”

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confidence: 85%

Linkage between Catecholate Siderophores and the Multicopper Oxidase CueO in Escherichia coli

et al. 2004

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The multicopper oxidase CueO had previously been demonstrated to exhibit phenoloxidase activity and was implicated in intrinsic copper resistance in Escherichia coli. Catecholates can potentially reduce Cu(II) to the prooxidant Cu(I). In this report we provide evidence that CueO protects E. coli cells by oxidizing enterobactin, the catechol iron siderophore of E. coli, in the presence of copper. In vitro, a mixture of enterobactin and copper was toxic for E. coli cells, but the addition of purified CueO led to their survival. Deletion of fur resulted in copper hypersensitivity that was alleviated by additional deletion of entC, preventing synthesis of enterobactin. In addition, copper added together with 2,3-dihydroxybenzoic acid or enterobactin was able to induce a ⌽(cueO-lacZ) operon fusion more efficiently than copper alone. The reaction product of the 2,3-dihydroxybenzoic acid oxidation by CueO that can complex Cu(II) ions was determined by gas chromatography-mass spectroscopy and identified as 2-carboxymuconate.

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confidence: 85%

Linkage between Catecholate Siderophores and the Multicopper Oxidase CueO in Escherichia coli

et al. 2004

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“…Interestingly, the genome sequence of its close relative Erwinia carotovora reveals the presence of at least one ViuB homologue, which could complement Fes activity as discussed above. A further fate of catecholate-containing ligands is oxidative inactivation, since catecholates are able to reduce Cu(II) into the prooxidant Cu(I), which in turn oxidizes catechols under conditions of ROS formation (156). The E. coli multicopper oxidase CueO, which is expressed in the presence of copper, oxidizes enterobactin and its degradation products (but also its catecholate precursors), leading to the formation of 2-carboxymuconate if DHB is the substrate (120).…”

Section: General Steps Of Siderophore Pathwaysmentioning

confidence: 99%

Siderophore-Based Iron Acquisition and Pathogen Control

Miethke

Marahiel

2007

Microbiol Mol Biol Rev

1,413

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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“…The multicopper oxidase CueO, a laccase-like enzyme present in the periplasm, which was suggested as the site of elevated oxidizable copper levels (35), is responsible for the oxidation of Cu(I) and also the siderophore enterobactin, which is a potential reductant for Cu(II) (17). Catecholate-containing ligands such as enterobactin, the major high-affinity iron scavenger in enteric bacteria (49), are able to reduce Cu(II) into Cu(I), which in turn may further oxidize compounds via formation of reactive oxygen species (ROS) (27). CueO, which is expressed in the presence of copper, oxidizes enterobactin, its catecholate precursors, and its degradation products, leading to the formation of 2-carboxymuconate if 2,3-dihydroxybenzoate is the substrate (18).…”

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Copper Stress Affects Iron Homeostasis by Destabilizing Iron-Sulfur Cluster Formation in Bacillus subtilis

et al. 2010

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Copper and iron are essential elements for cellular growth. Although bacteria have to overcome limitations of these metals by affine and selective uptake, excessive amounts of both metals are toxic for the cells. Here we investigated the influences of copper stress on iron homeostasis in Bacillus subtilis, and we present evidence that copper excess leads to imbalances of intracellular iron metabolism by disturbing assembly of iron-sulfur cofactors. Connections between copper and iron homeostasis were initially observed in microarray studies showing upregulation of Fur-dependent genes under conditions of copper excess. This effect was found to be relieved in a csoR mutant showing constitutive copper efflux. In contrast, stronger Fur-dependent gene induction was found in a copper efflux-deficient copA mutant. A significant induction of the PerR regulon was not observed under copper stress, indicating that oxidative stress did not play a major role under these conditions. Intracellular iron and copper quantification revealed that the total iron content was stable during different states of copper excess or efflux and hence that global iron limitation did not account for copperdependent Fur derepression. Strikingly, the microarray data for copper stress revealed a broad effect on the expression of genes coding for iron-sulfur cluster biogenesis (suf genes) and associated pathways such as cysteine biosynthesis and genes coding for iron-sulfur cluster proteins. Since these effects suggested an interaction of copper and iron-sulfur cluster maturation, a mutant with a conditional mutation of sufU, encoding the essential iron-sulfur scaffold protein in B. subtilis, was assayed for copper sensitivity, and its growth was found to be highly susceptible to copper stress. Further, different intracellular levels of SufU were found to influence the strength of Fur-dependent gene expression. By investigating the influence of copper on cluster-loaded SufU in vitro, Cu(I) was found to destabilize the scaffolded cluster at submicromolar concentrations. Thus, by interfering with iron-sulfur cluster formation, copper stress leads to enhanced expression of cluster scaffold and target proteins as well as iron and sulfur acquisition pathways, suggesting a possible feedback strategy to reestablish cluster biogenesis.

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Kinetic Study of the Oxidation of Catechol by Aqueous Copper(II)

Cited by 45 publications

References 28 publications

Linkage between Catecholate Siderophores and the Multicopper Oxidase CueO in Escherichia coli

Linkage between Catecholate Siderophores and the Multicopper Oxidase CueO in Escherichia coli

Siderophore-Based Iron Acquisition and Pathogen Control

Copper Stress Affects Iron Homeostasis by Destabilizing Iron-Sulfur Cluster Formation in Bacillus subtilis

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