Structure-Based Optimization of Pyridoxal 5'-Phosphate-Dependent Transaminase Enzyme (BioA) Inhibitors that Target Biotin Biosynthesis in Mycobacterium tuberculosis.
Liu, F., Dawadi, S., Maize, K.M., Dai, R., Park, S.W., Schnappinger, D., Finzel, B.C., Aldrich, C.C.(2017) J Med Chem 60: 5507-5520
- PubMed: 28594172 
- DOI: https://doi.org/10.1021/acs.jmedchem.7b00189
- Primary Citation of Related Structures:  
4XJO, 4XJP, 5KGS, 5KGT - PubMed Abstract: 
The pyridoxal 5'-phosphate (PLP)-dependent transaminase BioA catalyzes the second step in the biosynthesis of biotin in Mycobacterium tuberculosis (Mtb) and is an essential enzyme for bacterial survival and persistence in vivo. A promising BioA inhibitor 6 containing an N-aryl, N'-benzoylpiperazine scaffold was previously identified by target-based whole-cell screening. Here, we explore the structure-activity relationships (SAR) through the design, synthesis, and biological evaluation of a systematic series of analogues of the original hit using a structure-based drug design strategy, which was enabled by cocrystallization of several analogues with BioA. To confirm target engagement and discern analogues with off-target activity, each compound was evaluated against wild-type (WT) Mtb in biotin-free and -containing medium as well as BioA under- and overexpressing Mtb strains. Conformationally constrained derivative 36 emerged as the most potent analogue with a K D of 76 nM against BioA and a minimum inhibitory concentration of 1.7 μM (0.6 μg/mL) against Mtb in biotin-free medium.
Organizational Affiliation: 
Department of Medicinal Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States.