Copper Homeostasis in Enterococcus hirae

Wunderli-Ye, Haibo; Solioz, Marc

doi:10.1007/978-1-4615-4859-1_23

Cited by 33 publications

(25 citation statements)

References 33 publications

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“…In this organism, a copper reductase activity which reduces extracellular Cu 2+ to Cu + at a rate of 0.14±0.03 nmol min 21 (10 8 cells) 21 at 500 mM copper was observed (Wunderli-Ye & Solioz, 1999). Copper reductase activity could also be observed in L. lactis IL1403 and was quantitatively assessed with a colorimetric assay, based on the formation of a pink complex of Cu + with bicinchoninic acid.…”

Section: Copper Reduction By L Lactis Exhibits Nonsaturable Kineticsmentioning

confidence: 87%

“…Copper reduction by L. lactis (Solioz & Stoyanov, 2003;Strausak & Solioz, 1997;Wunderli-Ye & Solioz, 1999). In this organism, a copper reductase activity which reduces extracellular Cu 2+ to Cu + at a rate of 0.14±0.03 nmol min 21 (10 8 cells) 21 at 500 mM copper was observed (Wunderli-Ye & Solioz, 1999).…”

Section: Copper Reduction By L Lactis Exhibits Nonsaturable Kineticsmentioning

confidence: 94%

“…Cu 2+ reduction by whole cells was assessed essentially as described previously (Wunderli-Ye & Solioz, 1999). Briefly, L. lactis was grown fermentatively to early stationary phase in M17 medium.…”

Section: Methodsmentioning

confidence: 99%

“…It has been shown that approximately 70 % of the copper reduction activity by cells was due to quinones and 10 % to copper reduction by the NADH dehydrogenase, NDH-2 (Rapisarda et al, 1999(Rapisarda et al, , 2002 Volentini et al, 2011). The Gram-positive bacteria Enterococcus hirae and Lactococcus lactis have also been reported to exhibit extracellular Cu 2+ reductase activities (Wunderli-Ye & Solioz, 1999;Rezaïki et al, 2008). It has been shown that quinones can be mediators of cupric ion reduction in lactococci, but the physiological role and the molecular details of these activities have not been fully clarified.…”

Section: Introductionmentioning

confidence: 99%

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Non-enzymic copper reduction by menaquinone enhances copper toxicity in Lactococcus lactis IL1403

et al. 2013

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Lactococcus lactis possesses a pronounced extracellular Cu 2+ -reduction activity which leads to the accumulation of Cu + in the medium. The kinetics of this reaction were not saturable by increasing copper concentrations, suggesting a non-enzymic reaction. A copper-reductasedeficient mutant, isolated by random transposon mutagenesis, had an insertion in the menE gene, which encodes O-succinylbenzoic acid CoA ligase. This is a key enzyme in menaquinone biosynthesis. The DmenE mutant was deficient in short-chain menaquinones, and exogenously added menaquinone complemented the copper-reductase-deficient phenotype. Haem-induced respiration of wild-type L. lactis efficiently suppressed copper reduction, presumably by competition by the bd-type quinol oxidase for menaquinone. As expected, the DmenE mutant was respiration-deficient, but could be made respiration-proficient by supplementation with menaquinone. Growth of wild-type cells was more copper-sensitive than that of the DmenE mutant, due to the production of Cu + ions by the wild-type. This growth inhibition of the wild-type was strongly attenuated if Cu + was scavenged with the Cu(I) chelator bicinchoninic acid. These findings support a model whereby copper is non-enzymically reduced at the membrane by menaquinones. Respiration effectively competes for reduced quinones, which suppresses copper reduction. These findings highlight novel links between copper reduction, respiration and Cu + toxicity in L. lactis.

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Section: Copper Reduction By L Lactis Exhibits Nonsaturable Kineticsmentioning

confidence: 87%

Section: Copper Reduction By L Lactis Exhibits Nonsaturable Kineticsmentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-enzymic copper reduction by menaquinone enhances copper toxicity in Lactococcus lactis IL1403

et al. 2013

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“…One of the best understood copper homeostasis systems is that of the Gram-positive bacterium Enterococcus hirae [8][9][10][11][12][13][14][15]. The control of copper concentration in this bacterium is regulated by the cop operon, which contains the four genes copY, copZ, copA, and copB.…”

Section: Regulation Of the Cop Operon And Copymentioning

confidence: 99%

Stalking metal-linked dimers

Pazehoski¹,

Collins²,

Boyle³

et al. 2008

Journal of Inorganic Biochemistry

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Analysis of the metal‐binding selectivity of the metallochaperone CopZ from Enterococcus hirae by electrospray ionization mass spectrometry

Urvoas

Amekraz

Moulin

et al. 2003

Rapid Comm Mass Spectrometry

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Metallochaperones are soluble proteins involved in metal transport and regulation in vivo. Copper metallochaperones belong to a structural family of metal binding domains displaying a ferredoxin-like fold (betaalphabetabetaalphabeta) and a consensus metal-binding motif MXCXXC. The metal-binding selectivities for this class of proteins are poorly documented so far. The present study focuses on the measurement of the selectivity of the copper metallochaperone CopZ from Enterococcus hirae for different metal ions using an experimental approach based on electrospray ionization mass spectrometry (ESI-MS). All the metal cations tested, i.e. Cu(I), Cu(II), Hg(II), Cd(II) and Co(II), form specific metal complexes with CopZ. The study of a chemically modified CopZ as well as variants of CopZ in the active site demonstrated that the complexes observed by ESI-MS, i.e. in the gas phase, corresponded to the complexes previously observed by other analytical methods in solution. Competition experiments allowed the classification of the metal ions by increasing affinities for CopZ as follows: Co << Cd < Hg < Cu. A dissociation constant in the range of 20 microM was determined for cobalt. The affinity of CopZ for the other metals tested was found to be higher, with dissociation constants smaller than micromolar.

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Copper Homeostasis in Enterococcus hirae

Cited by 33 publications

References 33 publications

Non-enzymic copper reduction by menaquinone enhances copper toxicity in Lactococcus lactis IL1403

Non-enzymic copper reduction by menaquinone enhances copper toxicity in Lactococcus lactis IL1403

Stalking metal-linked dimers

Analysis of the metal‐binding selectivity of the metallochaperone CopZ from Enterococcus hirae by electrospray ionization mass spectrometry

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