Effect of ATP and 2-oxoglutarate on the in vitro interaction between the NifA GAF domain and the GlnB protein of Azospirillum brasilense

Brazilian Journal of Medical and Biological Research

P. Sotomaior¹  L.m. Araújo¹  C.y. Nishikawa¹  L.f. Huergo¹  R.a. Monteiro¹  F.o. Pedrosa¹  L.s. Chubatsu¹  E.m. Souza¹ 

[1] ,Universidade Federal do Paraná Departamento de Bioquímica e Biologia Molecular Curitiba PR ,Brasil

关键词: Azospirillum brasilense;    NifA protein;    GlnB protein;    GAF domain;    Nitrogen fixation;   

DOI  :  

来源: SciELO

【 摘 要 】

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 N-truncated protein in response to fixed nitrogen levels. We also used pull-down assays to show in vitro interaction between the purified N-terminal GAF domain of NifA and the GlnB protein. The results showed that A. brasilense GlnB interacts directly with the NifA N-terminal domain and this interaction is dependent on the presence of ATP and 2-oxoglutarate.

【 授权许可】

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