|
|
|
|
|
| Nishikawa,C.Y.; Araújo,L.M.; Kadowaki,M.A.S.; Monteiro,R.A.; Steffens,M.B.R.; Pedrosa,F.O.; Souza,E.M.; Chubatsu,L.S.. |
| 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 the negative control by fixed nitrogen; the central domain interacts with the RNA polymerase σ54 co-factor and the C-terminal domain is involved in DNA binding. The central and C-terminal domains are linked by the interdomain linker (IDL). A conserved four-cysteine motif encompassing the end of the central domain and the IDL is probably involved in the oxygen-sensitivity of NifA. In the present study,... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Biological nitrogen fixation; Azospirillum brasilense; NifA protein. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000200004 |
| |
|
|
| Sotomaior,P.; Araújo,L.M.; Nishikawa,C.Y.; Huergo,L.F.; Monteiro,R.A.; Pedrosa,F.O.; Chubatsu,L.S.; Souza,E.M.. |
| 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 GlnB regulates NifA activity by direct interaction with the NifA N-terminal GAF domain, preventing the inhibitory effect of this domain under conditions of nitrogen fixation. In the present study, we show that an N-terminal truncated form of NifA no longer required GlnB for activity and lost regulation by ammonium. On the other hand, in trans co-expression of the N-terminal GAF domain inhibited the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Azospirillum brasilense; NifA protein; GlnB protein; GAF domain; Nitrogen fixation. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012001200005 |
| |
|
|
|
