Adaptation of Aerobically Growing<i>Pseudomonas aeruginosa</i>to Copper Starvation

Frangipani, Emanuela; Slaveykova, Vera I.; Reimmann, Cornelia; Haas, Dieter

doi:10.1128/jb.00450-08

Cited by 50 publications

(61 citation statements)

References 62 publications

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“…Interestingly, and as a complement to our findings, the opposite effect of increased Fur repression during copper starvation has also been observed in Pseudomonas aeruginosa (14). Although it is presumed that this was caused by lower demand for iron through the respiratory chain, a total knockout of all copper-dependent terminal oxidases did not change the effect of Fur target downregulation.…”

contrasting

confidence: 29%

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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confidence: 29%

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

et al. 2010

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“…The H ϩ /O ratio of the entire ETC terminated by CIO was lowest among the ETCs involving the other terminal oxidases, indicating that the utilization of CIO is not efficient for the generation of ATP. CIO is induced by inhibitors of the respiratory chain, cyanide and sodium nitroprusside (SNP), or by copper starvation (16,18,19,21). Thus, CIO acts as a complementary enzyme when the heme-copper oxidases are not functioning or are inhibited.…”

Section: Figmentioning

confidence: 99%

“…Inactivation of the other terminal oxidases by respiratory inhibitors or gene disruption also leads to significant upregulation of the cio genes (15)(16)(17)(18)(19)(20)(21). The upregulation of CIO in the stationary phase is probably because P. aeruginosa produces cyanide, which inhibits heme-copper oxidases, in the stationary phase.…”

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confidence: 99%

Enzymatic Characterization and In Vivo Function of Five Terminal Oxidases in Pseudomonas aeruginosa

et al. 2014

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The ubiquitous opportunistic pathogen Pseudomonas aeruginosa has five aerobic terminal oxidases: bo 3 -type quinol oxidase (Cyo), cyanide-insensitive oxidase (CIO), aa 3 -type cytochrome c oxidase (aa 3 ), and two cbb 3 -type cytochrome c oxidases (cbb 3 -1 and cbb 3 -2). These terminal oxidases are differentially regulated under various growth conditions and are thought to contribute to the survival of this microorganism in a wide variety of environmental niches. Here, we constructed multiple mutant strains of P. aeruginosa that express only one aerobic terminal oxidase to investigate the enzymatic characteristics and in vivo function of each enzyme. The K m values of Cyo, CIO, and aa 3 for oxygen were similar and were 1 order of magnitude higher than those of cbb 3 -1 and cbb 3 -2, indicating that Cyo, CIO, and aa 3 are low-affinity enzymes and that cbb 3 -1 and cbb 3 -2 are high-affinity enzymes. Although cbb 3 -1 and cbb 3 -2 exhibited different expression patterns in response to oxygen concentration, they had similar K m values for oxygen. Both cbb 3 -1 and cbb 3 -2 utilized cytochrome c 4 as the main electron donor under normal growth conditions. The electron transport chains terminated by cbb 3 -1 and cbb 3 -2 generate a proton gradient across the cell membrane with similar efficiencies. The electron transport chain of aa 3 had the highest proton translocation efficiency, whereas that of CIO had the lowest efficiency. The enzymatic properties of the terminal oxidases reported here are partially in agreement with their regulatory patterns and may explain the environmental adaptability and versatility of P. aeruginosa.

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“…Heme-copper oxidases comprise a family of three cytochrome c oxidases and one quinol oxidase that reduce dioxygen to water (62,63). In P. aeruginosa under copper-limiting conditions, the four heme-copper oxidases of a branched electron transport chain became defective, and respiration and aerobic growth are sustained by a cytochrome bd-type cyanideinsensitive oxidase, which lacks copper in its active site (64). Likewise, copper deprivation in the cyanobacterium Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

Structure and Mode of Action of Microplusin, a Copper II-chelating Antimicrobial Peptide from the Cattle Tick Rhipicephalus (Boophilus) microplus

Silva

Rezende

Rossi

et al. 2009

Journal of Biological Chemistry

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Microplusin, a Rhipicephalus (Boophilus) microplus antimicrobial peptide (AMP) is the first fully characterized member of a new family of cysteine-rich AMPs with histidine-rich regions at the N and C termini. In the tick, microplusin belongs to the arsenal of innate defense molecules active against bacteria and fungi. Here we describe the NMR solution structure of microplusin and demonstrate that the protein binds copper II and iron II. Structured as a single ␣-helical globular domain, microplusin consists of five ␣-helices: ␣1 (residues Gly-9 to Arg-21), ␣2 (residues Glu-27 to Asn-40), ␣3 (residues Arg-44 to Thr-54), ␣4 (residues Leu-57 to Tyr-64), and ␣5 (residues Asn-67 to Cys-80). The N and C termini are disordered. This structure is unlike any other AMP structures described to date. We also used NMR spectroscopy to map the copper binding region on microplusin. Finally, using the Gram-positive bacteria Micrococcus luteus as a model, we studied of mode of action of microplusin. Microplusin has a bacteriostatic effect and does not permeabilize the bacterial membrane. Because microplusin binds metals, we tested whether this was related to its antimicrobial activity. We found that the bacteriostatic effect of microplusin was fully reversed by supplementation of culture media with copper II but not iron II. We also demonstrated that microplusin affects M. luteus respiration, a copper-dependent process. Thus, we conclude that the antibacterial effect of microplusin is due to its ability to bind and sequester copper II.

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Adaptation of Aerobically GrowingPseudomonas aeruginosato Copper Starvation

Cited by 50 publications

References 62 publications

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

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

Enzymatic Characterization and In Vivo Function of Five Terminal Oxidases in Pseudomonas aeruginosa

Structure and Mode of Action of Microplusin, a Copper II-chelating Antimicrobial Peptide from the Cattle Tick Rhipicephalus (Boophilus) microplus

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