methyl viologen Dotaz Zobrazit nápovědu
FerB is a cytoplasmic flavoprotein from the soil bacterium Paracoccus denitrificans with a putative role in defense against oxidative stress. To further explore this hypothesis, we compared protein variations upon methyl viologen treatment in wild-type and FerB mutant strains by a quantitative proteomic analysis based on iTRAQ-3DLC-MS/MS analysis. The proteins showing the most prominent increase in abundance were assigned to carbon fixation and sulfur assimilatory pathways. By employing these proteins as indirect markers, oxidative stress was found to be 15% less severe in the wild-type than in the FerB-deficient mutant cells. Oxidative stress altered the levels of proteins whose expression is dependent on the transcriptional factor FnrP. The observed down-regulation of the fnrP regulon members, most notably that of nitrous oxide reductase, was tentatively explained by an oxidative degradation of the [4Fe-4S] center of FnrP leading to a protein form which no longer activates transcription. While the level of FerB remained relatively constant, two proteins homologous to FerB accumulated during oxidative stress. When their genes were expressed in Escherichia coli, neither of the protein products contained a bound flavin, whereas they both had a high activity of flavin reductase, one preferentially utilizing NADH and the other NADPH.
- MeSH
- bakteriální proteiny biosyntéza genetika MeSH
- flavoproteiny genetika metabolismus MeSH
- mutace * MeSH
- oxidační stres účinky léků genetika MeSH
- Paracoccus denitrificans genetika metabolismus MeSH
- paraquat farmakologie MeSH
- proteomika MeSH
- regulace genové exprese u bakterií účinky léků genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A comparative examination of reduced methyl [MV·](+) and benzyl [BV·](+) viologens (as artificial electron donors for quantitative estimation of the respiratory periplasmic (Nap) and membrane-embedded (Nar) nitrate reductases) using a newly constructed nap mutant strain of Paracocccus denitrificans was done. The activity with [MV·](+) was high in whole-cell assays, confirming that this compound donates electrons to Nar. Initial rates of the more lipophilic [BV·](+) were considerably lower, which was interpreted to be caused by an inhibition of the active transport of nitrate into the cells. Anionophoric activity of [BV·](+) was detectable but too low to effectively circumvent the inhibition of nitrate transporter.
- MeSH
- analýza jednotlivých buněk MeSH
- bakteriální proteiny chemie genetika metabolismus MeSH
- benzylviologen metabolismus MeSH
- dusičnany metabolismus MeSH
- kinetika MeSH
- nitrátreduktasa chemie genetika metabolismus MeSH
- oxidace-redukce MeSH
- Rhodobacteraceae chemie enzymologie genetika MeSH
- transport elektronů MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Health and Safety Guide, ISSN 0259-7268 No. 51
36 s. : tab., lit.
- Konspekt
- Chemie. Mineralogické vědy
- NLK Obory
- chemie, klinická chemie
- toxikologie
- NLK Publikační typ
- publikace WHO
