Nifa Activity
Mostrando 1-12 de 82 artigos, teses e dissertações.
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1. Effect of point mutations on Herbaspirillum seropedicae NifA activity
NifA is the transcriptional activator of the nif genes in Proteobacteria. It is usually regulated by nitrogen and oxygen, allowing biological nitrogen fixation to occur under appropriate conditions. NifA proteins have a typical three-domain structure, including a regulatory N-terminal GAF domain, which is involved in control by fixed nitrogen and not strictl
Braz J Med Biol Res. Publicado em: 10/07/2015
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2. Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense
Azospirillum brasilense is a diazotroph that associates with important agricultural crops and thus has potential to be a nitrogen biofertilizer. The A. brasilense transcription regulator NifA, which seems to be constitutively expressed, activates the transcription of nitrogen fixation genes. It has been suggested that the nitrogen status-signaling protein Gl
Braz J Med Biol Res. Publicado em: 2012-12
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3. Expression and characterization of an N-truncated form of the NifA protein of Azospirillum brasilense
Azospirillum brasilense is a nitrogen-fixing bacterium associated with important agricultural crops such as rice, wheat and maize. The expression of genes responsible for nitrogen fixation (nif genes) in this bacterium is dependent on the transcriptional activator NifA. This protein contains three structural domains: the N-terminal domain is responsible for
Brazilian Journal of Medical and Biological Research. Publicado em: 2012-02
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4. Streptococcus mutans GlnK protein: an unusual PII family member
Streptococcus mutans is a Gram-positive bacterium present in the oral cavity, and is considered to be one of the leading causes of dental caries. S. mutans has a glnK gene, which codes for a PII-like protein that is possibly involved in the integration of carbon, nitrogen and energy metabolism in several organisms. To characterize the GlnK protein of S. muta
Brazilian Journal of Medical and Biological Research. Publicado em: 2011-05
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5. Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense
NifA protein activates transcription of nitrogen fixation operons by the alternative s54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS) located at the -200/-100 position of nif promoters with the consensus motif TGTN10- ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-
Publicado em: 2010
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6. Sequencing and promoter analysis of the nifENXorf3orf5fdxAnifQ operon from Azospirillum brasilense Sp7
A 40-kb DNA region containing the major cluster of nif genes has been isolated from the Azospirillum brasilense Sp7 genome. In this region three nif operons have been identified: nifHDKorf1Y, nifENXorf3orf5fdxAnifQ and orf2nifUSVorf4. The operons containing nifENX and nifUSV genes are separated from the structural nifHDKorf1Y operon by about 5 kb and 10 kb,
Publicado em: 2010
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7. Modulation of NifA activity by PII in Azospirillum brasilense: evidence for a regulatory role of the NifA N-terminal domain.
Azospirillum brasilense NifA, which is synthesized under all physiological conditions, exists in an active or inactive from depending on the availability of ammonia. The activity also depends on the presence of PII, as NifA is inactive in a glnB mutant. To investigate further the mechanism that regulates NifA activity, several deletions of the nifA coding se
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8. The central domain of Rhizobium meliloti NifA is sufficient to activate transcription from the R. meliloti nifH promoter.
The Rhizobium meliloti nifA product (NifA) shares extensive homology in its central region and at its C-terminal end with Rhizobium leguminosarum DctD and with NtrC from several species. All three proteins are transcriptional activators of NtrA (RpoN)-RNA polymerase-dependent promoters. Several large deletions of R. meliloti NifA were constructed to investig
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9. Fnr Is Involved in Oxygen Control of Herbaspirillum seropedicae N-Truncated NifA Protein Activity in Escherichia coli
Herbaspirillum seropedicae is an endophytic diazotroph belonging to the β-subclass of the class Proteobacteria, which colonizes many members of the Gramineae. The activity of the NifA protein, a transcriptional activator of nif genes in H. seropedicae, is controlled by ammonium ions through its N-terminal domain and by oxygen through mechanisms that are not
American Society for Microbiology.
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10. Control of Herbaspirillum seropedicae NifA Activity by Ammonium Ions and Oxygen
The activity of a truncated form of Herbaspirillum seropedicae NifA in different genetic backgrounds showed that its regulatory domain is involved in nitrogen control but not in O2 sensitivity or Fe dependence. The model for nitrogen control involving PII could thus apply to the proteobacteria at large. NifA may have a role in controlling ADP-ribosylation of
American Society for Microbiology.
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11. In vitro activity of the nitrogen fixation regulatory protein NIFA.
We have detected activity of the nitrogen fixation regulatory protein NIFA of Klebsiella pneumoniae in vitro. To do so we directed synthesis of NIFA in a coupled transcription-translation system and detected its ability to activate expression of a translational fusion between the nifH and lacZ genes. We infer that NIFA stimulates initiation of transcription
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12. Purification and in vitro activities of the native nitrogen fixation control proteins NifA and NifL.
The prokaryotic enhancer-binding protein NifA stimulates transcription at a distance by binding to sequences upstream of nitrogen fixation (nif) promoters and catalyzing the formation of open promoter complexes by RNA polymerase containing the alternative sigma factor, sigma 54. The activity of NifA in vivo is modulated by the negative regulatory protein Nif