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Wang K, Ge X, Bo T, Chen Q, Chen G, Liu W. Interruption of the denitrification pathway influences cell growth and magnetosome formation in Magnetospirillum magneticum AMB-1. Lett Appl Microbiol 2011; 53:55-62. [PMID: 21517919 DOI: 10.1111/j.1472-765x.2011.03063.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Intracellular magnetosome synthesis in magnetotactic bacteria has been proposed to be a process involving functions of a variety of proteins. To learn more about the genetic control that is involved in magnetosome formation, nonmagnetic mutants are screened and characterized. METHODS AND RESULTS Conjugation-mediated transposon mutagenesis was applied to screen for nonmagnetic mutants of Magnetospirillum magneticum AMB-1 that were unable to respond to the magnetic field. A mutant strain with disruption of a gene locus encoding nitric oxide reductase was obtained. Growth and magnetosome formation under different conditions were further characterized. CONCLUSIONS Interruption of denitrification by inactivating nitric oxide reductase was responsible for the compromised growth and magnetosome formation in the mutant with shorter intracellular chains of magnetite crystals than those of wild-type cells under anaerobic conditions. Nevertheless, the mutant displayed apparently normal growth in aerobic culture. SIGNIFICANCE AND IMPACT OF THE STUDY Efficient denitrification in the absence of oxygen is not only necessary for maintaining cell growth but may also be required to derive sufficient energy to mediate the formation of magnetosome vesicles necessary for the initiation or activation of magnetite formation.
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Affiliation(s)
- K Wang
- The State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, Shandong, China
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2
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A simple and rapid GC/MS method for the simultaneous determination of gaseous metabolites. J Microbiol Methods 2010; 84:46-51. [PMID: 20971136 DOI: 10.1016/j.mimet.2010.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 10/13/2010] [Accepted: 10/13/2010] [Indexed: 11/20/2022]
Abstract
We modified and tuned a commercial model of a gas chromatography/mass spectrometry (GC/MS) instrument to develop a simple and rapid method for the simultaneous quantification of a variety of gas species. Using the developed method with the newly modified instrument, gas species such as H(2), N(2), O(2), CO, NO, CH(4), CO(2), and N(2)O, which are common components of microbial metabolism, were accurately identified based on their retention times and/or mass-to-charge ratios (m/z) in less than 2.5 min. By examining the sensitivities and dynamic ranges for the detection of H(2), N(2), O(2), CH(4), CO(2), and N(2)O, it was demonstrated that the method developed in this study was sufficient for accurately monitoring the production and the consumption of these gaseous species during microbial metabolism. The utility of the new method was demonstrated by a denitrification study with Pseudomonas aureofaciens ATCC 13985(T). This method will be suitable for a variety of applications requiring the identification of gaseous metabolites in microorganisms, microbial communities, and natural ecosystems.
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Bagyánszki M, Krecsmarik M, De Winter BY, De Man JG, Fekete E, Pelckmans PA, Adriaensen D, Kroese ABA, Van Nassauw L, Timmermans JP. Chronic alcohol consumption affects gastrointestinal motility and reduces the proportion of neuronal NOS-immunoreactive myenteric neurons in the murine jejunum. Anat Rec (Hoboken) 2010; 293:1536-42. [PMID: 20648573 DOI: 10.1002/ar.21192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alcohol consumption interferes with gastrointestinal transit causing symptoms in alcoholic patients. Nitric oxide (NO), synthesized by neuronal nitric oxide synthase (nNOS) plays an important role in the control of gastrointestinal motility. Our aim was to investigate whether chronic alcohol intake in a murine model induces gastrointestinal motility disturbances and affects the nitrergic myenteric neurons in the stomach and jejunum. Gastric emptying, small intestinal transit and geometric centre were measured in vivo after intragastric gavage of Evans blue. Nitrergic relaxations to electrical field stimulation (EFS) and exogenous NO were recorded in jejunal muscle strips in vitro. The proportion of nNOS-immunopositive myenteric neurons was assessed using PGP9.5 and nNOS immunostaining. After chronic alcohol consumption, gastric emptying and small intestinal transit were delayed compared with control mice, and the nitrergic nerve-mediated relaxations to EFS in the jejunum were decreased, whereas relaxations to exogenous NO did not differ. The proportion of nNOS-immunoreactive neurons did not change in the stomach, whereas in the jejunum the percentage decreased from 33% to 27% (P < 0.001) after chronic alcohol intake. The total number of myenteric neurons remained unchanged. These results suggest that chronic alcohol consumption disturbs gastric and small intestinal motility in vivo and in vitro and is associated with a decrease in the proportion of nNOS-immunoreactive myenteric neurons in the murine jejunum.
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Affiliation(s)
- Mária Bagyánszki
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium
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Cloning, Expression, and Purification of a Nitric Oxide Synthase-Like Protein from Bacillus cereus. Biochem Res Int 2009; 2010:489892. [PMID: 21188074 PMCID: PMC3005942 DOI: 10.1155/2010/489892] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Accepted: 09/02/2009] [Indexed: 01/11/2023] Open
Abstract
The nitric oxide synthase-like protein from Bacillus cereus (bcNOS) has been cloned, expressed, and characterized. This small hemeprotein (356 amino acids in length) has a mass of 43 kDa and forms a dimer. The recombinant protein showed similar spectral shifts to the mammalian NOS proteins and could bind the substrates L-arginine and N(G)-hydroxy-L-arginine as well as the ligand imidazole. Low levels of activity were recorded for the hydrogen peroxide-dependent oxidation of N(G)-hydroxy-L-arginine and L-arginine by bcNOS, while a reconstituted system with the rat neuronal NOS reductase domain showed no activity. The recombinant bcNOS protein adds to the complement of bacterial NOS-like proteins that are used for the investigation of the mechanism and function of NO in microorganisms.
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Lee B, Usov OM, Grigoryants VM, Myers WK, Shapleigh JP, Scholes CP. The role of arginine-127 at the proximal NO-binding site in determining the electronic structure and function of 5-coordinate NO-heme in cytochrome c' of Rhodobacter sphaeroides. Biochemistry 2009; 48:8985-93. [PMID: 19685879 DOI: 10.1021/bi900833f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cytochrome c' is a heme protein from a denitrifying variant of Rhodobacter sphaeroides which may serve to store and transport metabolic NO while protecting against NO toxicity. Its heme site bears resemblance through its 5-coordinate NO-binding capability to the regulatory site in soluble guanylate cyclase. A conserved arginine (Arg-127) abuts the 5-coordinate NO-heme binding site, and the alanine mutant R127A provided insight into the role of the Arg-127 in establishing the electronic structure of the heme-NO complex and in modifying the heme-centered redox potential and NO-binding affinity. By comparison to R127A, the wild-type Arg-127 was determined to increase the heme redox potential, diminish the NO-binding affinity, perturb and diminish the 14NO hyperfine coupling determined by ENDOR (electron nuclear double resonance), and increase the maximal electronic g-value. The larger isotropic NO hyperfine and the smaller maximal g-value of the R127A mutant together predicted that the Fe-N-O bond angle in the mutant is larger than that of the Arg-127-containing wild-type protein. Deuterium ENDOR provided evidence for exchangeable H/D consistent with hydrogen bonding of Arg-127, but not Ala-127, to the O of the NO. Proton ENDOR features previously assigned to Phe-14 on the distal side of the heme were unperturbed by the proximal side R127A mutation, implying the localized nature of that mutational perturbation at the proximal, NO-binding side of the heme. From this work two functions of positively charged Arg-127 emerged: the first was to maintain the KD of the cytochrome c' in the 1 microM range, and the second was to provide a redox potential that enhances the stability of the ferrous heme.
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Affiliation(s)
- Byunghoon Lee
- Department of Chemistry, Center for Biochemistry and Biophysics, University at Albany, State University of New York, Albany, New York 12222, USA
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6
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Bergaust L, Shapleigh J, Frostegård A, Bakken L. Transcription and activities of NOx reductases in Agrobacterium tumefaciens: the influence of nitrate, nitrite and oxygen availability. Environ Microbiol 2008; 10:3070-81. [PMID: 18312398 DOI: 10.1111/j.1462-2920.2007.01557.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The ability of Agrobacetrium tumefaciens to perform balanced transitions from aerobic to anaerobic respiration was studied by monitoring oxygen depletion, transcription of nirK and norB, and the concentrations of nitrite, nitric oxide (NO) and nitrous oxide in stirred batch cultures with different initial oxygen, nitrate or nitrite concentrations. Nitrate concentrations (0.2-2 mM) did not affect oxygen depletion, nor the oxygen concentration at which denitrification was initiated (1-2 microM). Nitrite (0.2-2 mM), on the other hand, retarded the oxygen depletion as it reached approximately 20 microM, and caused initiation of active denitrification as oxygen concentrations reached 10-17 microM. Unbalanced transitions occurred in treatments with high cell densities (i.e. with rapid transition from oxic to anoxic conditions), seen as NO accumulation to muM concentrations and impeded nitrous oxide production. This phenomenon was most severe in nitrite treatments, and reduced the cells' ability to respire oxygen during subsequent oxic conditions. Transcripts of norB were only detectable during the period with active denitrification. In contrast, nirK transcripts were detected at low levels both before and after this period. The results demonstrate that the transition from aerobic to anaerobic metabolism is a regulatory challenge, with implications for survival and emission of trace gases from denitrifying bacteria.
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Affiliation(s)
- Linda Bergaust
- Department of Chemistry, Biotechnology and Food Sciences, Norwegian University of Life Sciences, As, Norway.
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8
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Stuehr DJ, Griffith OW. Mammalian nitric oxide synthases. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 65:287-346. [PMID: 1373932 DOI: 10.1002/9780470123119.ch8] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- D J Stuehr
- Department of Medicine, Cornell University Medical College, New York, New York
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9
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Choi PS, Naal Z, Moore C, Casado-Rivera E, Abruña HD, Helmann JD, Shapleigh JP. Assessing the impact of denitrifier-produced nitric oxide on other bacteria. Appl Environ Microbiol 2006; 72:2200-5. [PMID: 16517672 PMCID: PMC1393196 DOI: 10.1128/aem.72.3.2200-2205.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 01/09/2006] [Indexed: 11/20/2022] Open
Abstract
A series of experiments was undertaken to learn more about the impact on other bacteria of nitric oxide (NO) produced during denitrification. The denitrifier Rhodobacter sphaeroides 2.4.3 was chosen as a denitrifier for these experiments. To learn more about NO production by this bacterium, NO levels during denitrification were measured by using differential mass spectrometry. This revealed that NO levels produced during nitrate respiration by this bacterium were in the low muM range. This concentration of NO is higher than that previously measured in denitrifiers, including Achromobacter cycloclastes and Paracoccus denitrificans. Therefore, both 2.4.3 and A. cycloclastes were used in this work to compare the effects of various NO levels on nondenitrifying bacteria. By use of bacterial overlays, it was found that the NO generated by A. cycloclastes and 2.4.3 cells during denitrification inhibited the growth of both Bacillus subtilis and R. sphaeroides 2.4.1 but that R. sphaeroides 2.4.3 caused larger zones of inhibition in the overlays than A. cycloclastes. Both R. sphaeroides 2.4.3 and A. cycloclastes induced the expression of the NO stress response gene hmp in B. subtilis. Taken together, these results indicate that there is variability in the NO concentrations produced by denitrifiers, but, irrespective of the NO levels produced, microbes in the surrounding environment were responsive to the NO produced during denitrification.
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Affiliation(s)
- Peter S Choi
- Cornell University, Department of Microbiology, Wing Hall, Ithaca, NY 14853, USA
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10
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Yin S, Fuangthong M, Laratta WP, Shapleigh JP. Use of a green fluorescent protein-based reporter fusion for detection of nitric oxide produced by denitrifiers. Appl Environ Microbiol 2003; 69:3938-44. [PMID: 12839764 PMCID: PMC165187 DOI: 10.1128/aem.69.7.3938-3944.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To determine if green fluorescent protein could be used as a reporter for detecting nitric oxide production, gfp was fused to nnrS from Rhodobacter sphaeroides 2.4.3. nnrS was chosen because its expression requires nitric oxide. The presence of the fusion in R. sphaeroides 2.4.3 resulted in a significant increase in fluorescent intensity of the cells, but only when nitrite reductase was active. Cells lacking nitrite reductase activity and consequently the ability to generate nitric oxide were only weakly fluorescent when grown under denitrification-inducing conditions. One of the R. sphaeroides strains unable to generate nitric oxide endogenously was used as a reporter to detect exogenously produced nitric oxide. Incubation of this strain with sodium nitroprusside, a nitric oxide generator, significantly increased its fluorescence intensity. Mixing of known denitrifiers with the reporter strain also led to significant increases in fluorescence intensity, although the level varied depending on the denitrifier used. The reporter was tested on unknown isolates capable of growing anaerobically in the presence of nitrate, and one of these was able to induce expression of the fusion. Analysis of the 16S rRNA gene sequence of this isolate placed it within the Thauera aromatica subgroup, which is known to contain denitrifiers. These experiments demonstrate that this green fluorescent protein-based assay provides a useful method for assessing the ability of bacteria to produce nitric oxide.
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Affiliation(s)
- Shixue Yin
- Department of Agronomy, Agricultural College, Yangzhou University, Yangzhou 225009, Jiangsu, People's Republic of China
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11
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Ueki Y, Nakamura H, Matsumoto K, Tominaga T, Miyake S, Kita Y, Katayama Y, Fukuyama S, Hirasawa Y, Yoshida K, Eguchi K. NOR-1: a nitric oxide releasing agent for calibrating low levels of nitric oxide by the chemiluminescence method. Blood Coagul Fibrinolysis 2002; 13:75-80. [PMID: 11914648 DOI: 10.1097/00001721-200203000-00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Nitric oxide (NO) is formed in small amounts in vivo and is rapidly oxidized by interacting with oxygen, making measurement of its level difficult. The chemiluminescence assay is the most widely used method for detecting NO and is extremely sensitive to very small amounts of NO. However, it is difficult to prepare small amounts of NO to be used as a standard for NO analysis. NOR-1, a derivative of NOR-3, is a newly discovered NO donor with rapid NO-releasing activity. We assessed the dynamics of NO release and decomposition using NOR-1. Our results demonstrate that NOR-1 is stable in dimethylsulfoxide (DMSO) and is able to dilute at lower concentration (to picomolar levels) by DMSO without decomposition. NOR-1 released persistently 1.4 more excess of NO with 15 min of incubation. There was a linear relationship between the concentration of NOR-1 and that of NO released from NOR-1 (r=0.997) These findings suggest that NOR-1 is a useful reagent for the calibration of lower NO detection.
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Affiliation(s)
- Y Ueki
- Department of Internal Medicine, Sasebo Chuo Hospital, Sasebo, Japan.
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12
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Adak S, Bilwes AM, Panda K, Hosfield D, Aulak KS, McDonald JF, Tainer JA, Getzoff ED, Crane BR, Stuehr DJ. Cloning, expression, and characterization of a nitric oxide synthase protein from Deinococcus radiodurans. Proc Natl Acad Sci U S A 2002; 99:107-12. [PMID: 11756668 PMCID: PMC117522 DOI: 10.1073/pnas.012470099] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2001] [Indexed: 11/18/2022] Open
Abstract
We cloned, expressed, and characterized a hemeprotein from Deinococcus radiodurans (D. radiodurans NO synthase, deiNOS) whose sequence is 34% identical to the oxygenase domain of mammalian NO synthases (NOSoxys). deiNOS was dimeric, bound substrate Arg and cofactor tetrahydrobiopterin, and had a normal heme environment, despite its missing N-terminal structures that in NOSoxy bind Zn(2+) and tetrahydrobiopterin and help form an active dimer. The deiNOS heme accepted electrons from a mammalian NOS reductase and generated NO at rates that met or exceeded NOSoxy. Activity required bound tetrahydrobiopterin or tetrahydrofolate and was linked to formation and disappearance of a typical heme-dioxy catalytic intermediate. Thus, bacterial NOS-like proteins are surprisingly similar to mammalian NOSs and broaden our perspective of NO biochemistry and function.
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Affiliation(s)
- Subrata Adak
- Department of Immunology, Cleveland Clinic, Cleveland, OH 44195, USA.
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13
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Koutný M. From no-confidence to nitric oxide acknowledgement: a story of bacterial nitric-oxide reductase. Folia Microbiol (Praha) 2001; 45:197-203. [PMID: 11271799 DOI: 10.1007/bf02908943] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The review briefly summarizes current knowledge of the bacterial nitric-oxide reductase (NOR). This membrane enzyme consists of two subunits, the smaller one contains haem C and the larger one two haems B and nonhaem iron. The protein sequence and structure of metal centres demonstrate the relationship of NOR to the family of terminal oxidases. The binuclear Fe-Fe reaction centre, consisting of antiferromagnetically coupled haem B and nonhaem iron, is analogous to Fe-Cu centre of terminal oxidases. The data on the structure and function of NOR and terminal oxidases suggest that all these enzymes are closely evolutionally related. The catalytic properties are determined most of all by the relatively high toxicity of nitric oxide as a substrate and the resulting strong need to maintain its concentration at nanomolar levels. A kinetic model of the action of the enzyme comprises substrate inhibition. NOR does not conserve the free energy of nitric oxide reduction because it does not work as a proton pump and, moreover, the protons coming into the reaction are taken from periplasm, i.e. they do not cross the membrane.
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Affiliation(s)
- M Koutný
- Department of Environmental Technology, Faculty of Technology Zlín, Brno University of Technology, 762 72 Zlín, Czechia.
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14
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Mechanisms of nitrous oxide production in the subtropical North Pacific based on determinations of the isotopic abundances of nitrous oxide and di-oxygen. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1465-9972(00)00031-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Koutný M, Kucera I. Kinetic analysis of substrate inhibition in nitric oxide reductase of Paracoccus denitrificans. Biochem Biophys Res Commun 1999; 262:562-4. [PMID: 10462514 DOI: 10.1006/bbrc.1999.1245] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The current kinetic model for the nitric oxide reductase reaction (Girsch, P., and de Vries, S. (1997) Biochim. Biophys. Acta 1318, 202-216) does not involve the concentration of an electron donor. Here we introduce this variable and show, both theoretically and experimentally, its role in determining the extent of substrate inhibition by the excess of nitric oxide. NO is found to inhibit competitively with the electron donor, possibly by binding to the oxidized form of the enzyme. The observed partial character of the inhibition is tentatively explained by a slow reduction of the non-productive NO complex.
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Affiliation(s)
- M Koutný
- Department of Biochemistry, Masaryk University, Kotlárská 2, Brno, CZ-61137, Czech Republic
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Oberhauser W, Haid R, Bachmann C, Stampfl T, Langes C, Kopacka H, Ongania KH, Brüggeller P. First complex of the monoprotonated trioxodinitrate anion: synthesis and characterization of [Hg2(HN2O3)2(NO3)2(Ph2PNHPPh2)2]. INORG CHEM COMMUN 1999. [DOI: 10.1016/s1387-7003(99)00063-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cammack R, Joannou CL, Cui XY, Torres Martinez C, Maraj SR, Hughes MN. Nitrite and nitrosyl compounds in food preservation. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1411:475-88. [PMID: 10320676 DOI: 10.1016/s0005-2728(99)00033-x] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Nitrite is consumed in the diet, through vegetables and drinking water. It is also added to meat products as a preservative. The potential risks of this practice are balanced against the unique protective effect against toxin-forming bacteria such as Clostridium botulinum. The chemistry of nitrite, and compounds derived from it, in food systems and bacterial cells are complex. It is known that the bactericidal species is not nitrite itself, but a compound or compounds derived from it during food preparation. Of a range of nitrosyl compounds tested, the anion of Roussin's black salt [Fe4S3(NO)7]- was the most inhibitory to C. sporogenes. This compound is active against both anaerobic and aerobic food-spoilage bacteria, while some other compounds are selective, indicating multiple sites of action. There are numerous possible targets for inhibition in the bacterial cells, including respiratory chains, iron-sulfur proteins and other metalloproteins, membranes and the genetic apparatus.
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Affiliation(s)
- R Cammack
- Division of Life Sciences, King's College, London W8 7AH, UK.
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18
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Al-Ajlouni AM, Gould ES. Electron Transfer. 139. Reductions with Trioxodinitrate, [N2O3]2-. Inorg Chem 1999. [DOI: 10.1021/ic981194a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
| | - Edwin S. Gould
- Department of Chemistry, Kent State University, Kent, Ohio 44242
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Morita H, Yoshikawa H, Sakata R, Nagata Y, Tanaka H. Synthesis of nitric oxide from the two equivalent guanidino nitrogens of L-arginine by Lactobacillus fermentum. J Bacteriol 1997; 179:7812-5. [PMID: 9401042 PMCID: PMC179746 DOI: 10.1128/jb.179.24.7812-7815.1997] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Ten strains of Lactobacillus fermentum that differed in origin converted metmyoglobin to nitrosylmyoglobin [a pentacoordinate nitric oxide (NO) complex of Fe(II) myoglobin] in MRS broth at pH 4.3. Of the 10 strains, L. fermentum IFO 3956 possessed the strongest capacity to convert metmyoglobin to nitrosylmyoglobin. This strain synthesizes NO enzymatically from the two equivalent guanidino nitrogens of L-arginine. To our knowledge, this demonstrates for the first time the production of NO synthesized from the guanidino nitrogens of L-arginine by lactic acid bacteria. IFO 3956 may possess a bacterial NO synthase.
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Affiliation(s)
- H Morita
- School of Veterinary Medicine, Azabu University, Sagamihara, Japan.
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Abstract
Denitrification is a distinct means of energy conservation, making use of N oxides as terminal electron acceptors for cellular bioenergetics under anaerobic, microaerophilic, and occasionally aerobic conditions. The process is an essential branch of the global N cycle, reversing dinitrogen fixation, and is associated with chemolithotrophic, phototrophic, diazotrophic, or organotrophic metabolism but generally not with obligately anaerobic life. Discovered more than a century ago and believed to be exclusively a bacterial trait, denitrification has now been found in halophilic and hyperthermophilic archaea and in the mitochondria of fungi, raising evolutionarily intriguing vistas. Important advances in the biochemical characterization of denitrification and the underlying genetics have been achieved with Pseudomonas stutzeri, Pseudomonas aeruginosa, Paracoccus denitrificans, Ralstonia eutropha, and Rhodobacter sphaeroides. Pseudomonads represent one of the largest assemblies of the denitrifying bacteria within a single genus, favoring their use as model organisms. Around 50 genes are required within a single bacterium to encode the core structures of the denitrification apparatus. Much of the denitrification process of gram-negative bacteria has been found confined to the periplasm, whereas the topology and enzymology of the gram-positive bacteria are less well established. The activation and enzymatic transformation of N oxides is based on the redox chemistry of Fe, Cu, and Mo. Biochemical breakthroughs have included the X-ray structures of the two types of respiratory nitrite reductases and the isolation of the novel enzymes nitric oxide reductase and nitrous oxide reductase, as well as their structural characterization by indirect spectroscopic means. This revealed unexpected relationships among denitrification enzymes and respiratory oxygen reductases. Denitrification is intimately related to fundamental cellular processes that include primary and secondary transport, protein translocation, cytochrome c biogenesis, anaerobic gene regulation, metalloprotein assembly, and the biosynthesis of the cofactors molybdopterin and heme D1. An important class of regulators for the anaerobic expression of the denitrification apparatus are transcription factors of the greater FNR family. Nitrate and nitric oxide, in addition to being respiratory substrates, have been identified as signaling molecules for the induction of distinct N oxide-metabolizing enzymes.
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Affiliation(s)
- W G Zumft
- Lehrstuhl für Mikrobiologie, Universität Fridericiana, Karlsruhe, Germany
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Chuy C, Falvello LR, Libby E, Santa-María JC, Tomás M. Complexes of the Trioxodinitrate Anion: Synthesis and Characterization of [Zn(II)(bipy)(H(2)O)(N(2)O(3))] and [Co(II)(bipy)(2)(N(2)O(3))]. Inorg Chem 1997; 36:2004-2009. [PMID: 11669815 DOI: 10.1021/ic961194f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first two complexes of the trioxodinitrate anion were prepared by reaction of Zn(bipy)Cl(2).1.5H(2)O (1.1.5H(2)O) with Na(2)N(2)O(3).H(2)O in water to produce Zn(II)(bipy)(H(2)O)(N(2)O(3)) (2) and an analogous reaction of Co(bipy)(2)Cl(2).2.5H(2)O (3.2.5H(2)O) to produce Co(II)(bipy)(2)(N(2)O(3)) (4). Both complexes are air-sensitive and crystallize in the monoclinic space group P2(1)/n. For 2.H(2)O T = 24-26 degrees C, Z = 4, a = 7.7595(6) Å, b = 9.4798(7) Å, c = 17.197(1) Å, beta = 98.142(7) degrees, and V = 1252.3(2) Å(3). The final residuals were R1 = 0.0452, wR2 = 0.1172, and quality-of-fit = 1.057. The final model consisted of the main structure and a minor, 4% disordered component. For 4.4H(2)O T = -123 degrees C, Z = 4, a = 9.0950(9) Å, b = 17.924(3) Å, c = 13.695(2) Å, beta = 90.32(1) degrees, and V = 2232.5(6) Å(3). The final least-squares residuals were R1 = 0.0859, wR2 = 0.1975, and quality-of-fit = 0.917. A network of hydrogen bonds involving the crystal water molecules and the coordinated trioxodinitrate anion was found in each case; in 4, a series of fused four- and eight-membered rings were found to be a dominant feature in the extended structure. The structural data and the IR spectrum indicate that the N-N bond of trioxodinitrate, 1.264(5) Å in the free anion, is longer for the coordinated anion (1.280(5) Å in 2 and 1.333(11) Å in 4).
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Affiliation(s)
- Carmen Chuy
- Escuela de Química, Universidad de Costa Rica, San José 2060, Costa Rica, and Department of Inorganic Chemistry, University of Zaragoza-CSIC, Plaza San Francisco s/n, 50009 Zaragoza, Spain
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Wu Q, Knowles R, Niven DF. Effect of ionophores on denitrification inFlexibacter canadensis. Can J Microbiol 1995. [DOI: 10.1139/m95-031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Denitrification by Flexibacter canadensis was investigated by measuring the production and (or) consumption of nitrite, nitric oxide (NO), and nitrous oxide (N2O) under anaerobic conditions. Carbonyl cyanide m-chlorophenylhydrazone (CCCP), carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), 2,4-dinitrophenol, and nigericin, but not valinomycin-K+inhibited the production of nitrite and N2O from nitrate by intact cells. However, CCCP, FCCP, 2,4-dinitrophenol, nigericin, and valinomycin-K+did not affect nitrite production from nitrate by cell-free extracts. These results suggest that nitrate transport was dependent on the transmembrane pH gradient but not on the membrane potential. CCCP, FCCP, and nigericin but not 2,4-dinitrophenol and valinomycin-K+caused NO accumulation during the reduction of nitrite, and also inhibited NO consumption and N2O production from nitrite by intact cells. These results preclude an explanation for NO accumulation based on the collapse of the proton motive force by ionophores, and imply that CCCP, FCCP, and nigericin perhaps dissociated a nitrite reductase–nitric oxide reductase complex, and (or) inhibited nitric oxide reductase specifically. 2,4-Dinitrophenol and CCCP did not inhibit the reduction of N2O to dinitrogen. Addition of ≤ 1.16 μM dissolved NO did not affect the production of nitrite from nitrate, or the disappearance of nitrite or N2O. The rate of NO consumption was linear with concentrations of dissolved NO up to 67 nM. Above 67 nM NO, NO consumption was inhibited, suggesting that NO is toxic to nitric oxide reductase.Key words: ionophores, denitrification, nitric oxide, Flexibacter canadensis.
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Ruggiero CE, Carrier SM, Tolman WB. Durch Cu-Komplexe vermittelte reduktive Disproportionierung von NO: Nachahmung der Bildung von N2O durch Kupferproteine und Heterogenkatalysatoren. Angew Chem Int Ed Engl 1994. [DOI: 10.1002/ange.19941060818] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Ye RW, Averill BA, Tiedje JM. Denitrification: production and consumption of nitric oxide. Appl Environ Microbiol 1994; 60:1053-8. [PMID: 8017903 PMCID: PMC201439 DOI: 10.1128/aem.60.4.1053-1058.1994] [Citation(s) in RCA: 162] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Affiliation(s)
- R W Ye
- Department of Microbiology, Michigan State University, East Lansing 48824
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Jones AM, Hollocher TC. Nitric oxide reductase of Achromobacter cycloclastes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90121-u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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27
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Affiliation(s)
- W G Zumft
- Lehrstuhl für Mikrobiologie, Universität Karlsruhe, Germany
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28
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Meulemans A. Continuous monitoring of N-nitroso-L-arginine using micro carbon electrode in rat brain. Neurosci Lett 1993; 157:7-12. [PMID: 7694192 DOI: 10.1016/0304-3940(93)90630-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Constitutive brain nitric oxide (NO) synthase is described as converting L-arginine into NO. NO is thought to be the cellular messenger released by endothelial cells, and was originally termed endothelial-derived relaxing factor (EDRF). The mechanisms of its synthesis remain unclear. Using microelectrode differential pulse voltammetry in the presence of cortical constitutive rat brain NO synthase, a peak was recorded at -1.66 V with respect to a Ag/AgCl reference electrode. This voltage peak, due to the reduction of N-nitroso-L-arginine, was increased in rat brain cortex after pharmacological stimulation with L-arginine or A-23187; whereas it was abolished following application of D-arginine, N-nitro-L-arginine or pure NO. Using laser doppler measurements, the secretion of N-nitroso-L-arginine was correlated to brain blood flow. These preliminary results suggest that N-nitroso-L-arginine is synthetized by constitutive brain NO synthase of vascular endothelial cells in rat brain cortex.
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Affiliation(s)
- A Meulemans
- Faculté de médecine Xavier-Bichat, Laboratoire de Biophysique, Paris, France
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Jüngst A, Zumft WG. Interdependence of respiratory NO reduction and nitrite reduction revealed by mutagenesis of nirQ, a novel gene in the denitrification gene cluster of Pseudomonas stutzeri. FEBS Lett 1992; 314:308-14. [PMID: 1468562 DOI: 10.1016/0014-5793(92)81495-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An open reading frame, designated nirQ, was identified upstream of nirS, the structural gene for the respiratory nitrite reductase of Pseudomonas stutzeri ZoBell. Its derived gene product (275 amino acids, M(r) = 30,554) shows similarity to the NtrC protein family of transcriptional activators. Deletion-replacement mutagenesis of the nirQ gene resulted in the simultaneous loss of nitrite reduction and NO reduction in vivo. However, both reductases were still synthesized, with only nitrite reductase being active in vitro. NO reductase was overproduced by a factor of about 2. Our results indicate that the systems for nitrite reduction and NO reduction are functionally coupled.
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Affiliation(s)
- A Jüngst
- Lehrstuhl für Mikrobiologie, Universität Karlsruhe, Germany
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31
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Hollocher TC, Kristjánsson JK. Thermophilic denitrifying bacteria: A survey of hot springs in Southwestern Iceland. FEMS Microbiol Ecol 1992. [DOI: 10.1111/j.1574-6941.1992.tb00005.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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32
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Brittain T, Blackmore R, Greenwood C, Thomson AJ. Bacterial nitrite-reducing enzymes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 209:793-802. [PMID: 1425687 DOI: 10.1111/j.1432-1033.1992.tb17350.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The enzymic reduction of nitrite takes place in a wide range of bacteria and is found to occur in denitrifying, assimilatory and dissimilatory pathways. In this review we describe the major molecular characteristics of the various enzymes employed in each of these processes.
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Affiliation(s)
- T Brittain
- Department of Biochemistry, University of Auckland, New Zealand
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Ye RW, Averill BA, Tiedje JM. Characterization of Tn5 mutants deficient in dissimilatory nitrite reduction in Pseudomonas sp. strain G-179, which contains a copper nitrite reductase. J Bacteriol 1992; 174:6653-8. [PMID: 1328160 PMCID: PMC207644 DOI: 10.1128/jb.174.20.6653-6658.1992] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Tn5 was used to generate mutants that were deficient in the dissimilatory reduction of nitrite for Pseudomonas sp. strain G-179, which contains a copper nitrite reductase. Three types of mutants were isolated. The first type showed a lack of growth on nitrate, nitrite, and nitrous oxide. The second type grew on nitrate and nitrous oxide but not on nitrite (Nir-). The two mutants of this type accumulated nitrite, showed no nitrite reductase activity, and had no detectable nitrite reductase protein bands in a Western blot (immunoblot). Tn5 insertions in these two mutants were clustered in the same region and were within the structural gene for nitrite reductase. The third type of mutant grew on nitrate but not on nitrite or nitrous oxide (N2O). The mutant of this type accumulated significant amounts of nitrite, NO, and N2O during anaerobic growth on nitrate and showed a slower growth rate than the wild type. Diethyldithiocarbamic acid, which inhibited nitrite reductase activity in the wild type, did not affect NO reductase activity, indicating that nitrite reductase did not participate in NO reduction. NO reductase activity in Nir- mutants was lower than that in the wild type when the strains were grown on nitrate but was the same as that in the wild type when the strains were grown on nitrous oxide. These results suggest that the reduction of NO and N2O was carried out by two distinct processes and that mutations affecting nitrite reduction resulted in reduced NO reductase activity following anaerobic growth with nitrate.
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Affiliation(s)
- R W Ye
- Department of Microbiology and Public Health, Michigan State University, East Lansing 48824
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Hollocher TC, Kristjánsson JK. Thermophilic denitrifying bacteria: A survey of hot springs in Southwestern Iceland. FEMS Microbiol Lett 1992. [DOI: 10.1111/j.1574-6968.1992.tb05767.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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35
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Ye RW, Arunakumari A, Averill BA, Tiedje JM. Mutants of Pseudomonas fluorescens deficient in dissimilatory nitrite reduction are also altered in nitric oxide reduction. J Bacteriol 1992; 174:2560-4. [PMID: 1556074 PMCID: PMC205894 DOI: 10.1128/jb.174.8.2560-2564.1992] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Five Tn5 mutants of Pseudomonas fluorescens AK-15 deficient in dissimilatory reduction of nitrite were isolated and characterized. Two insertions occurred inside the nitrite reductase structural gene (nirS) and resulted in no detectable nitrite reductase protein on a Western immunoblot. One mutant had Tn5 inserted inside nirC, the third gene in the same operon, and produced a defective nitrite reductase protein. Two other mutants had insertions outside of this nir operon and also produced defective proteins. All of the Nir- mutants characterized showed not only loss of nitrite reductase activity but also a significant decrease in nitric oxide reductase activity. When cells were incubated with 15NO in H2(18)O, about 25% of the oxygen found in nitrous oxide exchanged with H2O. The extent of exchange remained constant throughout the reaction, indicating the incorporation of 18O from H2(18)O reached equilibrium rapidly. In all nitrite reduction-deficient mutants, less than 4% of the 18O exchange was found, suggesting that the hydration and dehydration step was altered. These results indicate that the factors involved in dissimilatory reduction of nitrite influenced the subsequent NO reduction in this organism.
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Affiliation(s)
- R W Ye
- Department of Microbiology and Public Health, Michigan State University, East Lansing 48824-1325
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Turk T, Hollocher TC. Oxidation of dithiothreitol during turnover of nitric oxide reductase: evidence for generation of nitroxyl with the enzyme from Paracoccus denitrificans. Biochem Biophys Res Commun 1992; 183:983-8. [PMID: 1567412 DOI: 10.1016/s0006-291x(05)80287-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The stoichiometric relationship between thiol oxidized and NO reduced was studied for the reaction catalyzed by nitric oxide reductase from Paracoccus denitrificans. The reaction systems consisted of dithiothreitol, ascorbate, phenazine methosulfate, enzyme and NO, or that system minus ascorbate. The mole ratio of thiol groups oxidized to NO reduced was observed to be 2.3 to 1.5 over a range of NO from 0.09 to 0.35 mumol. A ratio of 1.0 was expected for the simple reduction of NO by 1-electron to N2O. The oxidation of additional thiol is attributed to the trapping of nitrosyl hydride (nitroxyl, NO/NOH) by thiol.
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Affiliation(s)
- T Turk
- Department of Biochemistry, Brandeis University, Waltham, MA 02254
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37
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Marker exchange of the structural genes for nitric oxide reductase blocks the denitrification pathway of Pseudomonas stutzeri at nitric oxide. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54420-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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38
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Jackson MA, Tiedje JM, Averill BA. Evidence for a NO-rebound mechanism for production of N2O from nitrite by the copper-containing nitrite reductase from Achromobacter cycloclastes. FEBS Lett 1991; 291:41-4. [PMID: 1936249 DOI: 10.1016/0014-5793(91)81099-t] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reduction of NO2- by the Cu-containing nitrite reductase from Achromobacter cycloclastes produces NO as the primary product initially, but as NO accumulates, NO production levels-off and N2O production becomes significant. Reaction of the enzyme with NO2- in the presence of NO increases the amount of N2O product significantly, while trapping the NO product as nitrosylhemoglobin or rapid removal of NO by sparging results in no detectable N2O production. Reaction of the enzyme with 15NO2- in the presence of 14NO results in rapid formation of the mixed isotope product (14N, 15N)O in ca. 45% yield. In contrast, the presence or absence of NO has no effect on N2O production by a prototypical heme cd1-containing nitrite reductase. These results are consistent with formation of a labile Cu(+)-NO+ species in the copper enzyme, which normally decomposes to NO. Production of N2O requires that the released NO must rebind to the enzyme to combine with a second NO2- or a species derived therefrom.
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Affiliation(s)
- M A Jackson
- Department of Chemistry, University of Virginia, Charlottesville 22901
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H218O isotope exchange studies on the mechanism of reduction of nitric oxide and nitrite to nitrous oxide by denitrifying bacteria. Evidence for an electrophilic nitrosyl during reduction of nitric oxide. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98771-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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40
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Dermastia M, Turk T, Hollocher T. Nitric oxide reductase. Purification from Paracoccus denitrificans with use of a single column and some characteristics. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99104-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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41
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Goretski J, Hollocher TC. Catalysis of nitrosyl transfer by denitrifying bacteria is facilitated by nitric oxide. Biochem Biophys Res Commun 1991; 175:901-5. [PMID: 2025262 DOI: 10.1016/0006-291x(91)91650-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Two denitrifying bacteria, Pseudomonas stutzeri and Achromobacter cycloclastes, were incubated with Na15NO2 and NaN3 under conditions that allowed catalysis of nitrosyl transfer from nitrite to azide. This transfer, which is presumed to be mediated by the heme- and copper-containing nitrite reductase of P. stutzeri and A. cycloclastes, respectively, leads to formation of isotopically mixed 14,15N2O, whereas denitrification leads to 15N2O. The conditions that emphasized nitrosyl transfer also partially inhibited the nitric oxide reductase system and led to accumulation of 15NO. Absorption of NO from the gas phase by acidic CrSO4 in a sidewell largely abolished nitrosyl transfer to azide. With these two organisms, which are thought to be representative of denitrifiers generally, catalysis of nitrosyl transfer seemed to depend on NO.
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Affiliation(s)
- J Goretski
- Department of Biochemistry, Brandeis University, Waltham, MA 02254
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Costa C, Macedo A, Moura I, Moura JJ, Le Gall J, Berlier Y, Liu MY, Payne WJ. Regulation of the hexaheme nitrite/nitric oxide reductase of Desulfovibrio desulfuricans, Wolinella succinogenes and Escherichia coli. A mass spectrometric study. FEBS Lett 1990; 276:67-70. [PMID: 2265715 DOI: 10.1016/0014-5793(90)80508-g] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dissimilatory nitrite reduction, carried out by hexaheme proteins, gives ammonia as the final product. Representatives of this enzyme group from 3 bacterial species can also reduce NO to either ammonia or N2O. The redox regulation of the nitrite/nitric oxide activities is discussed in the context of the denitrifying pathway.
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Affiliation(s)
- C Costa
- Centro de Tecnologia Química e Biológica (CTQB), Oeiras, Portugal
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Goretski J, Zafiriou OC, Hollocher TC. Steady-state nitric oxide concentrations during denitrification. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38430-3] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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