The lipolytic activity of LipJ, a stress-induced enzyme, is regulated by its C-terminal adenylate cyclase domain.

ABSTRACT

Aim: The confirmation of lipolytic activity and role of Rv1900c in the Mycobacterium physiology Methods:rv1900c/N-terminus domain (rv1900NT) were cloned in pET28a/Escherichia coli, purified by affinity chromatography and characterized. Results: A zone of clearance on tributyrin-agar and activity with pNP-decanoate confirmed the lipolytic activity of Rv1900c. The Rv1900NT demonstrated higher enzyme specific activity, Vmax and kcat, but Rv1900c was more thermostable. The lipolytic activity of Rv1900c decreased in presence of ATP. Mycobacterium smegmatis expressed rv1900c/rv1900NT-altered colony morphology, growth, cell surface properties and survival under stress conditions. The effect was more prominent with Rv1900NT as compared with Rv1900c. Conclusion: The study confirmed the lipolytic activity of Rv1900c and suggested its regulation by the adenylate cyclase domain and role in the intracellular survival of bacteria.

Lay abstract Tuberculosis (TB) remains the top contagious/infectious killer in the world. It is caused by the bacteria Mycobacterium tuberculosis. The bacteria resides/replicates in the immune cell that normally has to eradicate infectious microorganisms. Though the treatment of TB is available, the emergence of drug-resistant bacteria is of major concern. The treatment of drug-resistant TB has been reported to be more difficult due to lengthy and complex treatment regimens. Therefore, there is an urgent need for new and better drugs to treat TB/drug-resistant TB. For this purpose understanding the role of each protein in the physiology of mycobacteria is required. Lipids play a critical role in the intracellular survival of this pathogen in the host. Our study demonstrated that LipJ supported the intracellular survival of bacteria. Therefore, it could be a potential drug target.