Hit-to-lead identification against Rpf-interacting protein A (RipA) from M. tuberculosis

Tuberculosis remains the world deadliest disease from a single infectious agent. Thus, recent studies have focused on the identification of promising new targets for drug design to combat M. tuberculosis in both active and dormant states. In this scenario, the endopeptidase RipA has emerged as an attractive target for anti-TB drug development because it is essential for the control of mycobacterial cell growth and division. In this study, we identified the first active molecules targeting RipA. To do that, we screened a fragment-library of about six hundred molecules against the purified enzyme. A total of 09 hits were identified and validated. Protein-ligand binding affinities ranged from micromolar to low millimolar. It is worth mentioning that we find two molecules with KD = 90 µM, higher than the expected at this stage. To our knowledge, this is the first study that identifies hits for drug design targeting RipA.