Bacterial nitrate reductases: Molecular and biological aspects of nitrate reduction

González, Pablo J.; Correia, Cristina; Moura, Isabel; Brondino, Carlos D.; Moura, José J. G.

doi:10.1016/j.jinorgbio.2005.11.024

Cited by 226 publications

(192 citation statements)

References 92 publications

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“…The Nar enzyme is composed of three subunits: NarG (catalytic molybdenum-containing subunit), NarH ([Fe-S]-containing electron transfer subunit), and NarI (heme-containing membrane anchor subunit) (59 and reviewed in Ref. 60). Earlier work (10,(27)(28)(29)(30) indirectly implicated Nar in the production of NO by studying the nitrosating ability of E. coli.…”

Section: Discussionmentioning

confidence: 99%

Nitric Oxide Homeostasis in Salmonella typhimurium

Gilberthorpe

Poole

2008

Journal of Biological Chemistry

113

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Nitric oxide (NO) is generated in biological systems primarily via the activity of NO synthases and nitrate and nitrite reductases. Here we show that Salmonella enterica serovar Typhimurium (S. typhimurium) grown anaerobically with nitrate is capable of generating polarographically detectable NO after nitrite (NO 2 ؊ ) addition. NO accumulation is sensitive to the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. Neither an fnr mutant nor an fnr hmp double mutant produces NO, indicating the involvement in NO evolution from NO 2 ؊ of protein(s) positively regulated by FNR. Contrary to previous findings in Escherichia coli, we demonstrate that neither the periplasmic nitrite reductase (NrfA) nor the cytoplasmic nitrite reductase (NirB) is involved in NO production in S. typhimurium. However, mutant cells lacking the membrane-bound nitrate reductase, NarGHI, and membranes derived from these cells are unable to produce NO, demonstrating that, in wild-type S. typhimurium, this enzyme is responsible for NO production. Membrane terminal oxidases cannot account for the NO levels measured. The nitrate reductase inhibitor, azide, abrogates NO evolution by Salmonella, and production of NO occurs only in the absence from the assays of nitrate; both features reveal a marked similarity between the NO-generating activities of this bacterium and plants. Unlike the situation in E. coli, an S. typhimurium hmp mutant produces NO both aerobically and anaerobically. Under aerobic conditions, when a functional flavohemoglobin is present, no NO is detectable. We propose a homeostatic mechanism in S. typhimurium, in which NO produced from NO 2 ؊ by nitrate reductase derepresses Hmp expression (via FNR and NsrR) and NorV expression (via NorR) and thus limits NO toxicity.

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Section: Discussionmentioning

confidence: 99%

Nitric Oxide Homeostasis in Salmonella typhimurium

Gilberthorpe

Poole

2008

Journal of Biological Chemistry

113

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“…3. Gram-negative prokaryotic nitrate reductase enzymes (assimilatory nitrate reductase, NAS; and periplasmic nitrate reductase, NAP) and the enzymes involved in the downstream assimilation of nitrite or in the respiratory processing of nitrite to ammonium (respiratory ammonification) or nitrogen (denitrification) as adapted from the literature (solid lines) (Gonzá lez et al, 2006;Kroneck & Abt, 2002;Richardson et al, 2001). In Shewanella, two isoforms of NAP (NapEDABC, NAP-a; and NapDAGHB, NAP-b) are encoded in the genomes of most species.…”

Section: Quinones and Transcriptional Activators In Shewanellamentioning

confidence: 99%

The periplasmic nitrate reductase in Shewanella: the resolution, distribution and functional implications of two NAP isoforms, NapEDABC and NapDAGHB

2010

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In the bacterial periplasm, the reduction of nitrate to nitrite is catalysed by a periplasmic nitrate reductase (NAP) system, which is a species-dependent assembly of protein subunits encoded by the nap operon. The reduction of nitrate catalysed by NAP takes place in the 90 kDa NapA subunit, which contains a Mo-bis-molybdopterin guanine dinucleotide cofactor and one [4Fe"4S] iron-sulfur cluster. A review of the nap operons in the genomes of 19 strains of Shewanella shows that most genomes contain two nap operons. This is an unusual feature of this genus. The two NAP isoforms each comprise three isoform-specific subunits -NapA, a di-haem cytochrome NapB, and a maturation chaperone NapD -but have different membrane-intrinsic subunits, and have been named NAP-a (NapEDABC) and NAP-b (NapDAGHB). Sixteen Shewanella genomes encode both NAP-a and NAP-b. The genome of the vigorous denitrifier Shewanella denitrificans OS217 encodes only NAP-a and the genome of the respiratory nitrate ammonifier Shewanella oneidensis MR-1 encodes only NAP-b. This raises the possibility that NAP-a and NAP-b are associated with physiologically distinct processes in the environmentally adaptable genus Shewanella. IntroductionSpecies of the genus Shewanella are defined as pink-or salmon-coloured, Gram-negative, rod-shaped, facultative anaerobic bacteria with a single polar flagellum that are oxidase-and catalase-positive and can reduce trimethylamine N-oxide (TMAO) and nitrate (Venkateswaran et al., 1999). Almost all Shewanella species to date have been discovered in extreme aquatic or terrestrial environments, including deep-sea trench sediments, Antarctic ice cores, and sites contaminated with toxic compounds, including arsenic, remnants of military explosives or crude oil (Konstantinidis et al., 2009;Zhao et al., 2005Zhao et al., , 2006. Most Shewanella species are classifiable into one or more selected extremophilic subgroups: halophiles, psychrophiles or barophiles (Fredrickson et al., 2008;Hau & Gralnick, 2007;Pakchung et al., 2006). Most recently, Shewanella vesiculosa sp. nov. and Shewanella marina sp. nov. have been characterized from marine environments (Bozal et al., 2009;Park et al., 2009) and contribute to the 51 species of Shewanella identified at the time of writing (http://www.bacterio.cict.fr/). Some Shewanella species, most notably Shewanella oneidensis MR-1, can grow via the reduction of metal oxides -including Fe(III), Mn(IV), Cr(VI), U(VI), Tc(VI), V(V) -thiosulfate, elemental sulfur and arsenate (Burns & DiChristina, 2009;Carpentier et al., 2005;Konstantinidis et al., 2009;Malasarn et al., 2008;Murphy & Saltikov, 2007;Nealson & Saffarini, 1994;Nealson & Little, 1997). The respiratory versatility of Shewanella species has significant implications in bioremediation and in the assembly of microbial fuel cells (Fredrickson et al., 2008;Hou et al., 2009;Kim et al., 2002;Tiedje, 2002). Interest in the ecology and physiology of Shewanella at the genetic level is reflected by the 19 genome sequencing projects completed by the US ...

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“…Nitrate reduction occurs in the cell in order to incorporate nitrogen into biomolecules (assimilatory ammonification) as the final electron acceptor when bacteria are grown in anaerobic conditions (denitrification) and to eliminate energy excess generated by the cell metabolism (dissimilatory ammonification) [1][2][3]. Nitrate reductases (NRs) are enzymes that catalyze the reduction of nitrate according to the reaction:…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, Nap is the only example with a not well defined function. This was concluded from the fact that its maximal expression varies between the species and no transcription promoter or conserved DNA consensus related to the nitrogen metabolism have been found in all the operons that encode them [1]. Therefore, physiological functions such as minimization of the reducing power under certain conditions of growth [7][8][9][10][11][12], denitrification [13][14][15][16], and scavenging nitrate when it is limited in the medium [17] have been proposed for these enzymes.…”

Section: Introductionmentioning

confidence: 99%

EPR and redox properties of periplasmic nitrate reductase from Desulfovibrio desulfuricans ATCC 27774

et al. 2006

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Nitrate reductases are enzymes that catalyze the conversion of nitrate to nitrite. We report here electron paramagnetic resonance (EPR) studies in the periplasmic nitrate reductase isolated from the sulfatereducing bacteria Desulfovibrio desulfuricans ATCC 27774. This protein, belonging to the dimethyl sulfoxide reductase family of mononuclear Mo-containing enzymes, comprises a single 80-kDa subunit and contains a Mo bis(molybdopterin guanosine dinucleotide) cofactor and a [4Fe-4S] cluster. EPR-monitored redox titrations, carried out with and without nitrate in the potential range from 200 to À500 mV, and EPR studies of the enzyme, in both catalytic and inhibited conditions, reveal distinct types of Mo(V) EPR-active species, which indicates that the Mo site presents high coordination flexibility. These studies show that nitrate modulates the redox properties of the Mo active site, but not those of the [4Fe-4S] center. The possible structures and the role in catalysis of the distinct Mo(V) species detected by EPR are discussed.

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Bacterial nitrate reductases: Molecular and biological aspects of nitrate reduction

Cited by 226 publications

References 92 publications

Nitric Oxide Homeostasis in Salmonella typhimurium

Nitric Oxide Homeostasis in Salmonella typhimurium

The periplasmic nitrate reductase in Shewanella: the resolution, distribution and functional implications of two NAP isoforms, NapEDABC and NapDAGHB

EPR and redox properties of periplasmic nitrate reductase from Desulfovibrio desulfuricans ATCC 27774

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