Abstract

VIRTUAL SCREENING OF DRUG LIKE INHIBITORS AGAINST ASPARTATE SEMIALDEHYDE DEHYDROGENASE OF LYSINE/ DAP PATHWAY OF MYCOBACTERIUM TUBERCULOSIS

Kaur D*, Gutte M. and Panke S.

Abstract

Tuberculosis (TB) is a major infectious disease killing nearly two million people, mostly in developing countries, every year. Mycobacterium tuberculosis (MTB) is the most common bacterial agent responsible for TB, however, M. bovis, M. microti canetti, and M. africanum can also result in TB. Many strains of tuberculosis resist the drugs most used to treat the disease. The increasing incidence of resistance of Mycobacterium tuberculosis strains to the most-effective (first-line) anti-TB drugs is a major factor contributing to the current TB epidemic. Drug-resistant strains have evolved mainly due to incomplete or improper treatment of TB patients. This alarming rate of antibiotic resistance to existing drugs calls for exploration of metabolic pathways for finding novel drug targets and even for prioritization of the known drug targets. The Lysine/DAP (diaminopimelate) biosynthetic pathway is a promising target due its specific role in cell wall and amino acid biosynthesis. The present study aims to evaluate the Aspartate semialdehyde dehydrogenase (ASADH; PDB id: 3LLG), an enzyme that controls the second step in the pathway for the conversion of Aspartyl phosphate to Aspartate semialdehyde as a promising drug target. Studies demonstrated with the two data sets were generated in order to screen potential inhibitors against Mtb drug target ASADH. The library of first data set comprised of analogues of aspartyl phosphate that is substrate for ASADH. The library of second data set comprised of antibacterial compounds obtained from Pubchem after drug like filtration. There were 76 compounds in first dataset and 9 compounds in second data set. Finally these compounds were docked to the active site of Mtb ASADH to select inhibitors establishing favorable interactions. The best inhibitors were docked into ASADH-NADPH complex to confirm their inhibitory activity with the complex as NADPH acts as a cofactor to the enzyme action. These applied virtual screening procedures helped in the identification of several potent candidates that possess inhibitory activity against Mtb ASADH. Therefore, these novel scaffolds/candidates which could have the potential to inhibit Mtb ASADH enzyme would represent promising starting points as lead compounds and certainly aid the experimental designing of anti-tubercular in lesser time.

Keywords: Mycobacterium Tuberculosis, Antibiotic Resistance; Lysine/ DAP Pathway.