In silico approach to identify the role of a putative protein MAP1138c in the virulence of Johne’s disease

The complete sequencing of Mycobacterium avium subspecies paratuberculosis (MAP) strain K-10 genome has shown the existence of over 4,000 genes. This opens up many opportunities to study the interaction of MAP with its hosts and the environment. Understanding the immune response directed at MAP antigens at different stages of infection, would be enhanced by the characterization of putative antigens. In this context, our comprehensive in silico analysis of MAP1138c, a putative protein demonstrates its sequential, physicochemical, structural and functional homology with Rv1411c (LprG) lipoprotein. The InterPro Scan studies have also shown that MAP1138c protein is a member of LppX/LprAFG family of lipoprotein involved in cell wall biogenesis and pathogenesis of Mycobacterium species. The structure assessment tools reveal that the theoretical structure of MAP1138c protein generated by SWISS-MODEL server shows homology with the crystal structure of Rv1411c (LprG) lipoprotein with respect to the global, local and stereochemical properties. Additionally, the structure-based ligand interaction studies using AutoDock Vina 1.1.2 shows that the triacylated glycoprotein (Ac1PIM2) also interacts with the hydrophobic pockets in the 3D theoretical structure of MAP1138c protein. Similar interactions of Rv1411c (LprG)-Ac1PIM2 leads to Toll-like Receptor 2 (TLR-2) mediated evasion of immune responses within host macrophages in tuberculosis infection. Hence, these results support our hypothesis that the MAP1138c protein is probably involved in immune evasion within host macrophages leading to virulence and infection in ruminants and human, respectively.