Interaction between GInB and the N-terminal domain of NifA in Azospirillum brasilense

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2008,（22）
• 页码范围: 3546-3552
• 页数: 7页
• 语种: 英文
• DOI: 10.1007/s11434-008-0435-x

摘要

Azospirillum brasilense is a diazotroph associated with many important agricultural crops and shows potential as a biofertilizer. NifA, the transcriptional activator of nitrogen fixation (nif) genes, and GInB, one of P,, signal transduction family protein, are key proteins in the regulation of nitrogen fixation in A. brasilense. It was previously reported that the regulation of NifA activity in A. brasilense depends on GInB. We report here that GInB was found to interact directly with the N-terminal domain of NifA in vivo under nitrogen-free conditions and the N-terminal mutant of NifA in which the Tyr residues at position 18 and 53 were replaced by Phe (NifA-N-Y18/53F) strengthened the interaction with GInB. Moreover, we also found that the amino acid residues 66-88 and 165-176 in N-terminus of NifA are responsible for the interaction with GInB.