Investigation of the role of Mycobacterium tuberculosis Protein Kinaz B in signal transduction by moleculer modelling approachesi

Tuberculosis caused by Mycobacterium Tuberculosis (Mtb) is one of the most lethal diseases. Therefore, it is a strategic goal to design drugs against this bacterium, which emploes 11 (A-K) eukaryotic-like ser/thr kinases in the signal transduction mechanism in the growth and proliferation processes. Knowing the roles of these kinases and targeting them are important drug design targets. In this study, we aimed to investigate the role of protein kinase G (PknG) in signal transduction by using computer assisted approaches. The missing part of the protein was completed by molecular modelling calculations. The corresponding threonines were phosphorylated and the effect of the phosphorylation on the conformation of the protein was observed by molecular dynamic calculations. The conformational changes in phsophorylated PknG were found to be very significant in its ability to bind to glycogen accumulation regulator (GarA). Docking results indicate that PknB-T171 rather than PknB-T179 forms a complex with an orientation to phosphorylate THR22. In this complex, phosphorylated THR171 interacts with ARG81, ARG96 and ARG97 in GarA. Besides, ASP and ARG189 in PknB-T171 interact with ARG26 and GLU32 and ASP34, respectively. All calculations were performed by AMBER (Assisted Model Building with Energy Refinement) and protein-protien interactions were studied by Z-DOCK.