Tuberculosis (TB) remains a significant global health burden, necessitating the discovery of new therapeutic strategies. In this study, we targeted phenyloxazoline synthase MbtB, a crucial enzyme in the iron acquisition pathway of Mycobacterium tuberculosis, which is vital for bacterial survival under iron-limited conditions. Recognizing MbtB as a promising drug target, we aimed to identify potential inhibitors from a curated library of FDA-approved drugs available in the ZINC database.

To simulate the enzyme’s binding environment, multiple conformations of the substrate’s transition state were used as query models. Conformational ensembles of both the query structures and library compounds were generated using Balloon (v1.8.2). Virtual screening was performed using ShaEP (v1.4.0), which compares molecules based on shape and electrostatic potential similarities. This approach led to the identification of several promising candidates that closely mimic the transition state structure of the MbtB substrate.

The top five hits from the screening were subjected to molecular dynamics simulations to evaluate their binding stability and interactions with the target protein at the atomic level. These leading compounds will be procured and tested for anti-TB activity under both iron-rich and iron-depleted conditions, in accordance with previously established methodologies. This study presents a structure-based strategy for repurposing FDA-approved drugs to target iron metabolism in M. tuberculosis.