Mycobacterium tuberculosis (M.tb), the causative agent of tuberculosis (TB), is one of the world's deadliest diseases. Roughly 1/3 of the global population is infected with TB and it remains the leading cause of death amongst people positive for HIV. The current treatment for active TB involves a drug cocktail of oral pills administered daily for 6-9 months. Since there have not been any new front-line drugs discovered since 1998, this remains the only major treatment available. Drug regimen stringency has led to patient incompliance and multi-drug resistant strains, demonstrating a dire need for new treatment options. An unexploited target for tuberculosis drugs is mycobacterial protein-protein interactions (PPIs). PPIs are a critical component of biosynthetic, metabolic, and regulatory processes essential for bacterial viability and/or in vivo survival. Our approach to discovering PPI inhibitors is based upon the M-PFC assay, which tags proteins of interest and emits a fluorescent signal upon successful dimerization. We aim to create a library of M-PFC assay strains using M. smegmatis, surrogates to M.tb, that contain PPIs previously validated in literature as important for pathogenesis. These strains will then be used to identify inhibitors of PPIs. The current project focuses on mabA, a strong homodimer of the FAS-II complex involved in mycolic acid synthesis. Current frontline drugs Isoniazid and Ethambutol also target this TB-specific cell wall component. Our first aim is to develop a drug screening assay that shows measurably significant binding of mabA. Since the assay is for screening, we will optimize its parameters for a high-throughput drug screen to obtain optimal Z-factors. In parallel, we are also developing approaches to validate whether PPIs are druggable targets using an inducible protein expression system. This will allow us to assess whether blocking dimerization will actually lead to death of the pathogen. We predict that overexpression of mabA can 1) interrupt dimerization in our MPF-C strain and 2) lead to loss of viability in M.tb. This will provide proof of principle that we can indeed find a small molecule to inhibit the PPI and lead to the desired killing of TB.

Finding novel tuberculosis drugs that target essential protein interactions

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.