The nitrate reductase of Paracoccus denitrificans

1986 ◽  
Vol 14 (6) ◽  
pp. 1204-1204
Author(s):  
ANNA L. CRASKE ◽  
STUART J. FERGUSON
Keyword(s):  
Nitrate Reductase ◽  
Paracoccus Denitrificans

Molybdenum incorporation in denitrifying Azospirillum brasilense Sp7

1992 ◽  
Vol 38 (10) ◽  
pp. 1042-1047 ◽  
Author(s):  
Christian Chauret ◽  
Wilfredo L. Barraquio ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Key Words ◽  
Nitrate Reduction ◽  
Gel Electrophoresis ◽  
Azospirillum Brasilense ◽  
Paracoccus Denitrificans ◽  
Free Medium ◽  
Azospirillum Brasilense Sp7

Nondenaturating disc gel electrophoresis revealed that 99Mo was incorporated into the nitrate reductase of Azospirillum brasilense grown in the absence but not in the presence of tungstate. Under denitrifying conditions, A. brasilense grown in tungsten-free medium steadily accumulated 99Mo for 12 h. In contrast, Paracoccus denitrificans grown under the same conditions ceased uptake after 1 h. However, both bacteria were incapable of accumulating significant amounts of 99Mo in media containing 10 mM tungstate, even though nitrate was reduced by A. brasilense. Aerobically grown A. brasilense cells transported 99Mo more efficiently than anaerobically grown cells. Key words: Azospirillum brasilense, tungsten, molybdenum incorporation, nitrate reduction.

Identification of an assimilatory nitrate reductase in mutants of Paracoccus denitrificans GB17 deficient in nitrate respiration

1997 ◽  
Vol 167 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Heather J. Sears ◽  
Phillip J. Little ◽  
D. J. Richardson ◽  
B. C. Berks ◽  
Stephen Spiro ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Paracoccus Denitrificans ◽  
Nitrate Respiration

A composite biochemical system for bacterial nitrate and nitrite assimilation as exemplified by Paracoccus denitrificans

2011 ◽  
Vol 435 (3) ◽  
pp. 743-753 ◽  
Author(s):  
Andrew J. Gates ◽  
Victor M. Luque-Almagro ◽  
Alan D. Goddard ◽  
Stuart J. Ferguson ◽  
M. Dolores Roldán ◽  
...  
Keyword(s):  
Nitrate Reductase ◽  
Nitrogen Source ◽  
Nitrite Reductase ◽  
Paracoccus Denitrificans ◽  
Gene Clusters ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Nitrite Reduction ◽  
Anaerobic Growth ◽  
Nitrate And Nitrite

The denitrifying bacterium Paracoccus denitrificans can grow aerobically or anaerobically using nitrate or nitrite as the sole nitrogen source. The biochemical pathway responsible is expressed from a gene cluster comprising a nitrate/nitrite transporter (NasA), nitrite transporter (NasH), nitrite reductase (NasB), ferredoxin (NasG) and nitrate reductase (NasC). NasB and NasG are essential for growth with nitrate or nitrite as the nitrogen source. NADH serves as the electron donor for nitrate and nitrite reduction, but only NasB has a NADH-oxidizing domain. Nitrate and nitrite reductase activities show the same Km for NADH and can be separated by anion-exchange chromatography, but only fractions containing NasB retain the ability to oxidize NADH. This implies that NasG mediates electron flux from the NADH-oxidizing site in NasB to the sites of nitrate and nitrite reduction in NasC and NasB respectively. Delivery of extracellular nitrate to NasBGC is mediated by NasA, but both NasA and NasH contribute to nitrite uptake. The roles of NasA and NasC can be substituted during anaerobic growth by the biochemically distinct membrane-bound respiratory nitrate reductase (Nar), demonstrating functional overlap. nasG is highly conserved in nitrate/nitrite assimilation gene clusters, which is consistent with a key role for the NasG ferredoxin, as part of a phylogenetically widespread composite nitrate and nitrite reductase system.

scholarly journals The location of dissimilatory nitrite reductase and the control of dissimilatory nitrate reductase by oxygen in Paracoccus denitrificans

1980 ◽  
Vol 192 (1) ◽  
pp. 231-240 ◽  
Author(s):  
P R Alefounder ◽  
S J Ferguson
Keyword(s):  
Plasma Membrane ◽  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Paracoccus Denitrificans ◽  
Osmotic Shock ◽  
Inhibitory Effect ◽  
Nitrate Respiration ◽  
Permeability Barrier ◽  
Intact Cells ◽  
Close Relationship

1. A method is described for preparing spheroplasts from Paracoccus denitrificans that are substantially depleted of dissimilatory nitrate reductase (cytochrome cd) activity. Treatment of cells with lysozyme + EDTA together with a mild osmotic shock, followed by centrifugation, yielded a pellet of spheroplasts and a supernatant that contained d-type cytochrome. The spheroplasts were judged to have retained an intact plasma membrane on the basis that less than 1% of the activity of a cytoplasmic marker protein, malate dehydrogenase, was released from the spheroplasts. In addition to a low activity towards added nitrite, the suspension of spheroplasts accumulated the nitrite that was produced by respiratory chain-linked reduction of nitrate. It is concluded that nitrate reduction occurs at the periplasmic side of the plasma membrane irrespective of whether nitrite is generated by nitrate reduction or is added exogenously. 2. Further evidence for the integrity of the spheroplasts was that nitrate reduction was inhibited by O2, and that chlorate was reduced at a markedly lower rate than nitrate. These data are taken as evidence for an intact plasma membrane because it was shown that cells acquire the capability to reduce nitrate under aerobic conditions after addition of low amounts of Triton X-100 which, with the same titre, also overcame the permeability barrier to chlorate reduction by intact cells. The close relationship between the appearance of chlorate reduction and the loss of the inhibitory effect of O2 on nitrate reduction also suggests that the later feature of nitrate respiration is due to a control on the accessibility of nitrate to its reductase rather than on the flow of electrons to nitrate reductase.

scholarly journals Investigation by electron paramagnetic resonance spectroscopy of the molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans

1988 ◽  
Vol 252 (3) ◽  
pp. 925-926 ◽  
Author(s):  
N Turner ◽  
A L Ballard ◽  
R C Bray ◽  
S Ferguson
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Paracoccus Denitrificans ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Species Comparison ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Respiratory Nitrate Reductase ◽  
Active Centres

The molybdenum centre of respiratory nitrate reductase from Paracoccus denitrificans has been investigated by e.p.r. spectroscopy of Mo(V). In common with the centres of the analogous enzymes from Escherichia coli and Pseudomonas aeruginosa, it undergoes a pH- and anion-dependent transition between two different e.p.r. signal-giving species. Comparison of the relevant e.p.r. parameters extracted with the help of computer simulations reveals ligation of the metal in the active centres of the three enzymes to be identical.

scholarly journals Interference of chlorate and chlorite with nitrate reduction in resting cells of Paracoccus denitrificans

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3529-3534 ◽  
Author(s):  
Igor Kučera
Keyword(s):  
Cell Membrane ◽  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Paracoccus Denitrificans ◽  
Metabolic Activation ◽  
Partial Purification ◽  
Resting Cells ◽  
Aerobic Growth ◽  
Membrane Bound ◽  
Periplasmic Enzyme

When grown anaerobically on a succinate+nitrate (SN) medium, Paracoccus denitrificans forms the membrane-bound, cytoplasmically oriented, chlorate-reducing nitrate reductase Nar, while the periplasmic enzyme Nap is expressed during aerobic growth on butyrate+oxygen (BO) medium. Preincubation of SN cells with chlorate produced a concentration-dependent decrease in nitrate utilization, which could be ascribed to Nar inactivation. Toluenization rendered Nar less sensitive to chlorate, but more sensitive to chlorite, suggesting that the latter compound may be the true inactivator. The Nap enzyme of BO cells was inactivated by both chlorate and chlorite at concentrations that were at least two orders of magnitude lower than those shown to affect Nar. Partial purification of Nap resulted in insensitivity to chlorate and diminished sensitivity to chlorite. Azide was specific for SN cells in protecting nitrate reductase against chlorate attack, the protective effect of nitrate being more pronounced in BO cells. The results are discussed in terms of different metabolic activation of chlorine oxoanions in both types of cells, and limited permeation of chlorite across the cell membrane.

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