Respiratory Transformation of Nitrous Oxide (N2O) to Dinitrogen by Bacteria and Archaea

Zumft, Walter G.; Kroneck, Peter M. H.

doi:10.1016/s0065-2911(06)52003-x

Cited by 303 publications

(368 citation statements)

References 420 publications

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“…The reduction of N 2 O is a thermodynamically favorable reaction with DG & -104.6 kJ mol -1 but its thermodecomposition is kinetically inert owing to the activation barrier of approximately 250 kJ mol -1 , which is consistent with a spin-forbidden process [21,71]. Although N 2 O is a weak ligand for metals, because it is a weak r-donor and weak p-acceptor molecule, several complexes of transition metals are able to bind and activate N 2 O [72,73].…”

Section: Activation Of the Cuz Centermentioning

confidence: 80%

“…The CuZ center in form C has slightly different absorption bands and a slightly different EPR spectrum from the one in forms D and E, and the CuZ center in form C is redox-active, whereas in forms D and E it is redox-inactive [67,68] center exhibits absorption maxima at 480, 550, and 780 nm, the CuZ center in the form of CuZ* is characterized by an absorption band at 640 nm. The reduction of the purple N 2 OR (Table 1, form A) by sodium dithionite proceeds in two kinetic steps: a fast phase in which the absorbance at 540 nm decreases and the shoulder at 800 nm disappears almost within seconds, owing to the reduction of the CuA center (Table 1, form B), and a slower phase, in which a ''blue'' form is generated in the course of minutes (Table 1, form C), characterized by a decrease and almost disappearance of the 550-nm absorption band and an increase in the 640-nm absorption band [21]. Therefore, the enzyme when purified under the exclusion of oxygen can be in an ''as-isolated'' ( Table 1, form A), a ''semireduced'' ( Table 1, form B), and a ''dithionite-reduced'' (Table 1, form C) form.…”

Section: Spectroscopy Of the Different Redox States Of The Cuz Centermentioning

confidence: 99%

“…The CuZ center is responsible for the catalysis of the two-electron reduction of nitrous oxide (N 2 O) to nitrogen and water, the final step of the denitrification pathway [3,20,21]: The catalysis of this reaction plays an important environmental role, owing to the fact that N 2 O is a potent greenhouse gas. Moreover, the emission of this gas into the atmosphere was enhanced in the last century through the intensification of agriculture, the so-called green revolution, which increased the presence of nitrogen in soil through the application of synthetic nitrogen-based fertilizers [22,23].…”

Section: Introductionmentioning

confidence: 99%

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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: Activation Of the Cuz Centermentioning

confidence: 80%

Section: Spectroscopy Of the Different Redox States Of The Cuz Centermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2011

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“…Nitrous oxide (N 2 O) is considered as a major greenhouse gas and is a significant contributor to ozone layer destruction (Zumft and Kroneck, 2006). N 2 O is mainly produced by denitrification, a microbial respiratory process in which nitrate/nitrite is reduced to gaseous forms (NO, N 2 O and N 2 ); however, other microbial processes, such as nitrification and dissimilatory nitrate reduction to ammonium (DNRA), can also produce N 2 O (Conrad, 1996).…”

Section: Introductionmentioning

confidence: 99%

Identification and isolation of active N2O reducers in rice paddy soil

et al. 2011

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Dissolved N 2 O is occasionally detected in surface and ground water in rice paddy fields, whereas little or no N 2 O is emitted to the atmosphere above these fields. This indicates the occurrence of N 2 O reduction in rice paddy fields; however, identity of the N 2 O reducers is largely unknown. In this study, we employed both culture-dependent and culture-independent approaches to identify N 2 O reducers in rice paddy soil. In a soil microcosm, N 2 O and succinate were added as the electron acceptor and donor, respectively, for N 2 O reduction. For the stable isotope probing (SIP) experiment, 13 C-labeled succinate was used to identify succinate-assimilating microbes under N 2 O-reducing conditions. DNA was extracted 24 h after incubation, and heavy and light DNA fractions were separated by density gradient ultracentrifugation. Denaturing gradient gel electrophoresis and clone library analysis targeting the 16S rRNA and the N 2 O reductase gene were performed. For culture-dependent analysis, the microbes that elongated under N 2 O-reducing conditions in the presence of cell-division inhibitors were individually captured by a micromanipulator and transferred to a low-nutrient medium. The N 2 O-reducing ability of these strains was examined by gas chromatography/mass spectrometry. Results of the SIP analysis suggested that Burkholderiales and Rhodospirillales bacteria dominated the population under N 2 O-reducing conditions, in contrast to the control sample (soil incubated with only 13 C-succinate). Results of the single-cell isolation technique also indicated that the majority of the N 2 O-reducing strains belonged to the genera Herbaspirillum (Burkholderiales) and Azospirillum (Rhodospirillales). In addition, Herbaspirillum strains reduced N 2 O faster than Azospirillum strains. These results suggest that Herbaspirillum spp. may have an important role in N 2 O reduction in rice paddy soils.

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“…N 2 O ? N 2 ), namely the two-electron reduction of the kinetically inert molecule nitrous oxide (N 2 O) to dinitrogen (N 2 ) and water [1,2].…”

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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Respiratory Transformation of Nitrous Oxide (N2O) to Dinitrogen by Bacteria and Archaea

Cited by 303 publications

References 420 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

Identification and isolation of active N2O reducers in rice paddy soil

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

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