Structural insights of Mycobacterium GTPase-Obg and anti-sigma-F factor Usfx interaction

An essential protein for bacterial growth, GTPase-Obg (Obg), is known to play an unknown but crucial role in stress response as its expression increases in Mycobacterium under stress conditions. It is well reported that Obg interacts with anti-sigma-F factor Usfx; however, a detailed analysis and structural characterization of their physical interaction remain undone. In view of above-mentioned points, this study was conceptualized for performing binding analysis and structural characterization of Obg-Usfx interaction. The binding studies were performed by surface plasmon resonance, while in silico docking analysis was done to identify crucial residues responsible for Obg-Usfx interaction. Surface plasmon resonance results clearly suggest that N-terminal and G domains of Obg mainly contribute to Usfx binding. Also, binding constants display strong affinity that was further evident by intermolecular hydrogen bonds and hydrophobic interactions in the predicted complex. Strong interaction between Obg and Usfx supports the view that Obg plays an important role in stress response, essentially required for Mycobacterium survival. As concluded by various studies that Obg is crucial for Mycobacterium survival under stress, this structural information may help us in designing novel and potential inhibitors against resistant Mycobacterium strains.