Screening of the interacting proteins with NifA in <Emphasis Type="Italic">Azospirillum brasilense</Emphasis> Sp7 by the yeast two-hybrid system

NifA in AzospiriUum brasilense plays a key role in regulating the synthesis and activity of nitrogenase in response to ammonia and oxygen available. In this work we used the yeast two-hybrid system to identify the proteins that interact with NifA. The nifA gene was fused to the yeast two-hybrid vector pGBD-C2, and three A. brasilense Sp7 genomic libraries for use in yeast two-hybrid studies were constructed. Screening of the libraries identified four clones encoding proteins that interact with NifA. The confirmation of the interactions of each gene product of the four clones and NifA were carried out by exchanging the vectors for nifA and the four clones and by mutageneses of the four clones with shift reading frame experiments in yeast two-hybrid studies. DNA sequence analyses showed that two clones encode proteins containing PAS domains that play an important role in signal transduction. One clone has high similarity with the fhuE gene of Escherichia coli, whose gene product is involved in iron uptake and transportation, and the other clone encodes an unknown protein.     

Interaction between PⅡ and NifA in Azospirillum brasilense Sp7

The interaction between PⅡ and NifA in A.brasilense Sp7 was investigated by using the yeast two-hybrid system.Our experimental results showed that PⅡ directly interacted with the entire NifA protein and its N-terminal domain,but did not interact with the central domin and the C-terminal domain of NifA.No interaction happened if glnB coding for PⅡ was frame-shift mutated.Pz,a homolog of PⅡ,had no interation with NifA.     

Transcriptome analysis of Sinorhizobium meliloti nodule bacteria in nifA mutant background

Sinorhizobium meliloti is one genus of gram-nega- tive soil bacteria that can fix atmospheric nitrogen in root nodules of its symbiotic leguminous host plants[1]. Specific recognition and progressive differentiation ofboth bacteria and host cells are requ…     

PAS domain of the deduced Org35 protein mediates the interaction with NifA

PAS domains are sensory input domains and pro- tein-protein interaction sites that have been identified recently in a family of sensory proteins from all king-doms of life[1,2]. A variety of environmental stimuli such as light, oxygen, redox potential, an…