IN SILICO STUDIES OF NifH PROTEIN STRUCTURE AND ITS POST- TRANSLATIONAL MODIFICATION IN Bradyrhizobium sp. ORS278

Bradyrhizobium is a gram negative, symbiotic nitrogen fixer that can form nodules in the roots of leguminous plants. The enzyme nitrogenase is the utmost important component of nitrogen fixing machinery, comprising two proteins, a molydenum-iron protein (MoFe protein) and an iron protein (Fe protein). Since, there is no comprehensive data on the tertiary structure of the nitrogenase iron protein (NifH) of Bradyrhizobium sp. ORS278 in the public domain, we decided to construct a three dimensional structure of the protein based on homology modeling technique. The model was constructed using the crystal structure of the NifH protein (1NIP) from Azotobacter vinelandii as a template. The functionally important regions of the protein and position of 4Fe-4S cluster in the protein were investigated. The 3D model was further utilized to highlight the importance of covalent modification site (Arg-102) in post-translational regulation of the nitrogenase enzyme through in-silico docking experiment.