Biochemical characterization of PE_PGRS61 family protein of Mycobacterium tuberculosis H37Rv reveals the binding ability to fibronectin

Objective(s): The periodic binding of protein expressed by Mycobacterium tuberculosis H37Rv with the host cell receptor molecules i.e. fibronectin (Fn) is gaining significance because of its adhesive properties.  The genome sequencing of M. tuberculosis H37Rv revealed that the proline-glutamic (PE) proteins contain polymorphic GC-rich repetitive sequences (PGRS) which have clinical importance in pathogenesis events when the host encounters M. tuberculosis H37Rv.  The functional parts of PE_PGRS family proteins, have not been extensively studied in tuberculosis biology.  Materials and Methods: Fibronectin (10 ng and 20 ng) were used for FnBP assay and its enzymatic activities were observed by using various protein concentrations. Results: Therefore, in the present work, we cloned, expressed, purified and identified a novel PE_PGRS61 (Rv3653) family protein in M. tuberculosis H37Rv.  Our experiment, observation suggested that at particular concentrations of 10 ng and 20 ng of Fn exhibits optimum binding to the purified Fibronectin Binding Protein (FnBP), a PE_PGRS61 family protein at 0.20 µg and 0.25 µg concentrations, respectively. Moreover, for better understanding the computational analysis, the B-cell and T-cell epitopes prediction prospect some amino acid propensity scales with hydrophilicity and antigenic variation index at their respective locations.  Conclusion: Thus, the current findings provide an opportunity to illuminate the functions of PE_PGRS61 family protein.  So, in this point of view, it could be useful to develop a novel therapeutic approach or diagnostic pipeline through targeting these fibronectin binding protein (FnBP) expressing genes.