In silico identification and characterization of nifH protein of Azospirillum strains isolated from Solanum tuberosum L.

Abstract

Nitrogen (N) constitutes as a fundamental macronutrient necessary for maintaining plant health, metabolism, and overall survival. However, it exists in the soil in insoluble compound forms that plants cannot directly uptake. Biological N-fixation (BNF) is a fundamental process wherein atmospheric N2 is reduced to form biologically available ammonium, providing a key N source for plants. The process of BNF is carried out by a diverse yet limited group of microorganisms termed diazotrophs, using the nitrogenase enzyme. This enzyme complex includes two proteins: di-nitrogenase reductase iron protein (nifH), and di-nitrogenase molybdenum iron protein. Due to its significant conservation, the nifH gene serves as a valuable molecular marker for assessing the potential of N-fixation in various microorganisms. Therefore, the current study focused on a comprehensive computational exploration nifH gene and protein of Azospirillum strains (TN03 and TN22). This analysis includes the evaluation of their physicochemical traits, phylogenetic analysis, structural properties (including 3D models), quality assessment of models, and functional annotation analysis using various established bioinformatics tools. The protein of both strains showed an average molecular weight of approximately 14959 and 15313 Da, respectively, exhibited thermal stability and an acidic profile. Furthermore, this theoretical insight could aid researchers in understanding the structure of predicted protein and might facilitate the designing of genetically modified N-fixing bacteria through the design of specific primers.