Identification and characterization of SnrA, an inducible oxygen-insensitive nitroreductase in Salmonella enterica serovar Typhimurium TA1535

Nokhbeh, M.R.; Boroumandi, S.; Pokorny, Nicholas J.; Koziarz, P.; Paterson, E. Suzanne; Lambert, Iain B.

doi:10.1016/s0027-5107(02)00174-4

Cited by 34 publications

(33 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cells were cultured under diazotrophic conditions with 30 mM malate as the carbon source and in the presence of different compounds at a final concentration of 0.1 mM or 0.2 mM. The compounds used were nitrofuran derivatives that are substrates of NfsA and NfsB of E. coli (27); the prodrug CB1954, which is a substrate of NfsB of E. coli (7); 2-aminofluorene and benzo[a]pyrene, substrates of SnrA of Salmonella enterica (13); several dinitroaromatics, substrates of the nitroreductase of R. capsulatus E1F1 (4); salicylate, a MarR repressor, as 2,4-dinitrophenol (2); and paraquat, a SoxR activator (9).…”

Section: Resultsmentioning

confidence: 99%

“…Expression of the nprA gene was induced in the presence of the superoxide-generating compound paraquat ( Table 1). The oxygen-insensitive nitroreductases of E. coli and Salmonella, which are under the control of the MarRA system, are also induced in the presence of paraquat via the soxRS system (13,14). However, it has been postulated that nitroreductases can regulate the accumulation of electron donors in the bacterial cytosol (9).…”

Section: Figmentioning

confidence: 99%

See 1 more Smart Citation

Regulation and Characterization of Two Nitroreductase Genes, nprA and nprB , of Rhodobacter capsulatus

Pérez-Reinado

Blasco

Castillo

et al. 2005

Appl Environ Microbiol

View full text Add to dashboard Cite

Among photosynthetic bacteria, strains B10 and E1F1 of Rhodobacter capsulatus photoreduce 2,4-dinitrophenol (DNP), which is stoichiometrically converted into 2-amino-4-nitrophenol by a nitroreductase activity. The reduction of DNP is inhibited in vivo by ammonium, which probably acts at the level of the DNP transport system and/or physiological electron transport to the nitroreductase, since this enzyme is not inhibited by ammonium in vitro. Using the complete genome sequence data for strain SB1003 of R. capsulatus, two putative genes coding for possible nitroreductases were isolated from R. capsulatus B10 and disrupted. The phenotypes of these mutant strains revealed that both genes are involved in the reduction of DNP and code for two major nitroreductases, NprA and NprB. Both enzymes use NAD(P)H as the main physiological electron donor. The nitroreductase NprA is under ammonium control, whereas the nitroreductase NprB is not. In addition, the expression of the nprB gene seems to be constitutive, whereas nprA gene expression is inducible by a wide range of nitroaromatic and heterocyclic compounds, including several dinitroaromatics, nitrofuran derivatives, CB1954, 2-aminofluorene, benzo[a]pyrene, salicylic acid, and paraquat. The identification of two putative mar/sox boxes in the possible promoter region of the nprA gene and the induction of nprA gene expression by salicylic acid and 2,4-dinitrophenol suggest a role in the control of the nprA gene for the two-component MarRA regulatory system, which in Escherichia coli controls the response to some antibiotics and environmental contaminants. In addition, upregulation of the nprA gene by paraquat indicates that this gene is probably a member of the SoxRS regulon, which is involved in the response to stress conditions in other bacteria.Nitroaromatics are released into the environment almost exclusively as a consequence of anthropogenic activities related to explosives, paints, dyes, and pharmacology industries (23). Microorganisms have developed many different strategies to remove and degrade these xenobiotic compounds, and oxidative or reductive pathways for the degradation of nitroaromatics have been widely studied (19,23,29). Polynitroaromatic compounds are usually degraded through the following two major reductive pathways: (i) reduction of the aromatic ring by the addition of hydride ions to produce hydride-Meisenheimer complexes and (ii) reduction of the nitro group(s) to a hydroxylamino or amino group(s) by nitroreductases (3, 10, 15, 25). The oxygen-sensitive nitroreductases catalyze one electron step reaction to produce a nitro radical anion that can be reoxidized by oxygen with the concomitant production of superoxide. However, the best-studied nitroreductases are oxygen insensitive since they do not produce radicals and they catalyze the sequential addition of pairs of electrons donated by NAD(P)H to convert the nitro groups into hydroxylamines or amines, often through nitroso derivatives (15, 23). These enzymes are usually homodimers of a 25-kDa pol...

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Regulation and Characterization of Two Nitroreductase Genes, nprA and nprB , of Rhodobacter capsulatus

Pérez-Reinado

Blasco

Castillo

et al. 2005

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…The major oxygen-insensitive nitroreductase is encoded by the nfsA gene in E. coli and by snrA in Salmonella enterica (serovar Typhimurium) [Carroll et al, 2002;Nokhbeh et al, 2002]. The SnrA enzyme is present in some Ames tester strains (e.g., TA1535), but it is lacking in strains TA1538 and TA98 [Yamada et al, 1997;Nokhbeh et al, 2002].…”

Section: Discussionmentioning

confidence: 99%

Frameshift mutations induced by four isomeric nitroacridines and their des-nitro counterpart in thelacZ reversion assay inEscherichia coli

Hoffmann

Yin

Terry

et al. 2006

Environ. Mol. Mutagen.

View full text Add to dashboard Cite

Acridines are well-known as compounds that intercalate noncovalently between DNA base pairs and induce +/-1 frameshift mutations at sites of monotonous repeats of a single base. Reactive derivatives of acridines, including acridine mustards and nitroacridines, form covalent adducts in DNA and exhibit mutagenic properties different from the simple intercalators. We compared the frameshift mutagenicity of the cancer chemotherapy drug nitracrine (1-nitro-9-(3'-dimethylaminopropylamino)-acridine), its des-nitro counterpart 9-(3'-dimethylaminopropylamino)-acridine (DAPA), and its 2-, 3-, and 4-nitro isomers (2-, 3-, and 4-nitro-DAPA) in the lacZ reversion assay in Escherichia coli. DAPA is a simple intercalator, much like the widely studied 9-aminoacridine. It most strongly induced +/-1 frameshift mutations in runs of guanine residues and more weakly induced -1 frameshifts in a run of adenine residues. A nitro group in the 1, 3, or 4 position of DAPA reduced the yield of +/-1 frameshift mutations. DAPA weakly induced -2 frameshifts in an alternating CG sequence. In contrast, nitracrine and its 3-nitro isomer resembled the 3-nitroacridine Entozon in effectively inducing -2 frameshift mutations. The 2- and 4-nitro isomers were less effective than the 1- and 3-nitro compounds in -2 frameshift mutagenesis. The results are interpreted with respect to intercalation, steric interactions, effects of base strength on DNA binding, enzymatic processing, and a slipped mispairing model of frameshift mutagenesis.

show abstract

“…The possibility that the mechanism proceeds via a radical mechanism has been postulated. 33,43 Additionally, PETN reductase was also found to be active on structurally related N-nitramines, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, 'Royal Demolition Explosive') and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), however to a much lesser extent compared to nitrate esters. 44 …”

Section: Reductive Nitrate Ester Cleavagementioning

confidence: 99%

“…SnrA and CnR from Salmonella enterica serovar Typhimurium TA1535, 33 PnrA and PnrB from Pseudomonas putida, 34 and…”

mentioning

confidence: 99%

Unusual reactions mediated by FMN-dependent ene- and nitro-reductases

2013

View full text Add to dashboard Cite

Due to the chemical versatility of the flavin cofactor, FMN-dependent ene-reductases and nitroreductases can catalyze or mediate a diverse spectrum of chemical reactions. Among them, two-electron transfer reactions dominate, which may proceed via sequential hydride transfer at the same or at alternate reactive sites. In addition, highly reactive intermediates are often formed, which undergo subsequent spontaneous (non-enzymatic) reactions leading to further enzymatic transformations in a cascade. Besides the well-known reductive processes involving alkenes and nitro groups at the expense of a reduced flavin cofactor, redox-neutral processes including disproportionation and CvC-bond isomerization reactions are catalyzed by OYE homologues. Unusual flavin-dependent biotransformations are reviewed with a special focus on the OYE family of flavoproteins (ene-reductases) and oxygen-insensitive FMN-dependent nitro-reductases.

show abstract

Identification and characterization of SnrA, an inducible oxygen-insensitive nitroreductase in Salmonella enterica serovar Typhimurium TA1535

Cited by 34 publications

References 46 publications

Regulation and Characterization of Two Nitroreductase Genes, nprA and nprB , of Rhodobacter capsulatus

Regulation and Characterization of Two Nitroreductase Genes, nprA and nprB , of Rhodobacter capsulatus

Frameshift mutations induced by four isomeric nitroacridines and their des-nitro counterpart in thelacZ reversion assay inEscherichia coli

Unusual reactions mediated by FMN-dependent ene- and nitro-reductases

Contact Info

Product

Resources

About