10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 3 2012 (July - September) lessThan i greaterThan Bradyrhizobium lessThan /i greaterThan 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 lessThan i greaterThan Bradyrhizobium lessThan /i greaterThan 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 lessThan i greaterThan Azotobacter vinelandii lessThan /i greaterThan 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 lessThan i greaterThan in-silico lessThan /i greaterThan docking experiment. Subarna takur, asim k Bothra And Arnab Sen Bradyrhizobium, symbiotic, homology modeling, template, docking. 22-32