Structure-Guided Development of a Potent BioA Inhibitor Validates Biotin Synthesis Inhibition as a Therapeutic...

Structure-guided optimization was applied to develop a potent and selective inhibitor of the aminotransferase BioA, a key enzyme in bacterial biotin biosynthesis. Strategic modifications of a screening hit enhanced potency and pharmacokinetics, yielding C48, which binds BioA with a Ki of 200 pM and displays sub-micromolar MICs against Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria. Biochemical, structural, and genetic studies confirmed C48's mechanism of action. In vitro, C48 induced cell envelope stress and membrane remodeling, mimicking biotin starvation. Pharmacokinetic profiling revealed excellent oral bioavailability resulting in over 39,000-fold improved exposure versus the parent compound. To address the discrepancy in biotin levels between humans and mice, we developed a low-biotin mouse model that recapitulates human biotin physiology. In this model C48 reduced Mtb burden in lungs and spleen, providing the first in vivo proof-of-concept for targeting biotin biosynthesis as a therapeutic strategy against tuberculosis.