Pseudomonas stutzeri N2O reductase contains CuA-type sites.

Scott, Robert A.; Zumft, Walter G.; Coyle, C. L.; Dooley, David M.

doi:10.1073/pnas.86.11.4082

Cited by 83 publications

(52 citation statements)

References 34 publications

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“…These studies were followed by the study of Jin et al [48], who studied the copper centers in N 2 OR by electron spin echo spectroscopy and presented further evidence for the similarity between the CuA center in the two enzymes. This similarity was also shown by magnetic circular dichroism (MCD) [49,50] and extended X-ray absorption fine structure (EXAFS) studies, as the curve-fitted copper EXAFS results for N 2 OR are strikingly similar to those for COX [50][51][52]. Finally, the identification of a set of potential copper ligands in the C-terminal domain of N 2 OR, which matched the ones of the CuA center in COX, was crucial to establish that the CuA center, initially believed to be unique to COX, is also present in N 2 OR [53,54] (Fig.…”

Section: The History Of the Cuz Centersupporting

confidence: 58%

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

et al. 2011

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This review focuses on the novel CuZ center of nitrous oxide reductase, an important enzyme owing to the environmental significance of the reaction it catalyzes, reduction of nitrous oxide, and the unusual nature of its catalytic center, named CuZ. The structure of the CuZ center, the unique tetranuclear copper center found in this enzyme, opened a novel area of research in metallobiochemistry. In the last decade, there has been progress in defining the structure of the CuZ center, characterizing the mechanism of nitrous oxide reduction, and identifying intermediates of this reaction. In addition, the determination of the structure of the CuZ center allowed a structural interpretation of the spectroscopic data, which was supported by theoretical calculations. The current knowledge of the structure, function, and spectroscopic characterization of the CuZ center is described here. We would like to stress that although many questions have been answered, the CuZ center remains a scientific challenge, with many hypotheses still being formed.

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Section: The History Of the Cuz Centersupporting

confidence: 58%

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

et al. 2011

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“…N,OR was purified under anaerobic conditions by procedures previously described [7] and stored in liquid nitrogen until use. The copper content was determined by atomic absorbance spectroscopy and the Volume 294, number I,2…”

Section: Methodsmentioning

confidence: 99%

A model of the copper centres of nitrous oxide reductase (Pseudomonas stutzeri)

Farrar¹,

Thomson²,

Cheesman³

et al. 1991

FEBS Letters

122

118

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Nitrous oxide reductase (N2OR), Pseudomonas stutzeri, catalyses the 2 electron reduction of nitrous oxide to di‐nitrogen. The enzyme has 2 identical subunits (M 1 ∼ 70 000) of known amino acid sequence and contains ∼ 4 Cu ions per subunit. By measurement of the optical absorption, electron paramagnetic resonance (EPR) and low‐temperature magnetic circular dichroism (MCD) spectra of the oxidised state, a semi‐reduced form and the fully reduced state of the enzyme it is shown that the enzyme contains 2 distinct copper centres of which one is assigned to an electron‐transfer function, centre A, and the other to a catalytic site, centre Z. The latter is a binuclear copper centre with at least 1 cysteine ligand and cycles between oxidation levels Cu(II)/Cu(II) and Cu(II)/Cu(I) in the absence of substrate or inhibitors. The state Cu(II)/Cu(I) is enzymatically inactive. The MCD spectra provide evidence for a second form of centre Z, which may be enzymatically active, in the oxidised state of the enzyme. Centre A is structurally similar to that of CuA in bovine and bacterial cytochrome c oxidase and also contains copper ligated by cysteine. This centre may also be a binuclear copper complex.

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“…The binuclear copper centre, CuA, is an electron transfer centre similar to the CuA found in cytochrome oxidases and its properties have been extensively studied [6][7][8][9]. CuZ is a novel mixed-valence copper centre (Cu 4 S) with a sulfide ion bridging a distorted tetrahedron of copper atoms, a unique structural feature in biology.…”

Section: Introductionmentioning

confidence: 99%

A new CuZ active form in the catalytic reduction of N2O by nitrous oxide reductase from Pseudomonas nautica

et al. 2010

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The final step of bacterial denitrification, the two-electron reduction of N 2 O to N 2 , is catalyzed by a multicopper enzyme named nitrous oxide reductase. The catalytic centre of this enzyme is a tetranuclear copper site called CuZ, unique in biological systems. The in vitro reconstruction of the activity requires a slow activation in the presence of the artificial electron donor, reduced methyl viologen, necessary to reduce CuZ from the resting nonactive state (1Cu II /3Cu I ) to the fully reduced state (4Cu I ), in contrast to the turnover cycle, which is very fast. In the present work, the direct reaction of the activated form of Pseudomonas nautica nitrous oxide reductase with stoichiometric amounts of N 2 O allowed the identification of a new reactive intermediate of the catalytic centre, CuZ°, in the turnover cycle, characterized by an intense absorption band at 680 nm. Moreover, the first mediated electrochemical study of Ps. nautica nitrous oxide reductase with its physiological electron donor, cytochrome c-552, was performed. The intermolecular electron transfer was analysed by cyclic voltammetry, under catalytic conditions, and a second-order rate constant of (5.5 ± 0.9) 9 10 5 M -1 s -1 was determined. Both the reaction of stoichiometric amounts of substrate and the electrochemical studies show that the active CuZ°species, generated in the absence of reductants, can rearrange to the resting non-active CuZ state. In this light, new aspects of the catalytic and activation/inactivation mechanism of the enzyme are discussed.

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Pseudomonas stutzeri N2O reductase contains CuA-type sites.

Cited by 83 publications

References 34 publications

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

The tetranuclear copper active site of nitrous oxide reductase: the CuZ center

A model of the copper centres of nitrous oxide reductase (Pseudomonas stutzeri)

A new CuZ active form in the catalytic reduction of N2O by nitrous oxide reductase from Pseudomonas nautica

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