Bisubstrate Inhibitors of Biotin Protein Ligase in Mycobacterium tuberculosis Resistant to Cyclonucleoside Formation.

Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, is the leading cause bacterial infectious diseases mortality. Biotin protein ligase (BirA) globally regulates lipid metabolism in Mtb through the posttranslational biotinylation of acyl coenzyme A carboxylases (ACCs) involved in lipid biosynthesis and is essential for Mtb survival. We previously developed a rationally designed bisubstrate inhibitor of BirA that displays potent enzyme inhibition and whole-cell activity against multidrug resistant and extensively drug resistant Mtb strains. Here we present the design, synthesis and evaluation of a focused series of inhibitors, which are resistant to cyclonucleoside formation, a key decomposition pathway of our initial analogue. Improved chemical stability is realized through replacement of the adenosyl N-3 nitrogen and C-5' oxygen atom with carbon as well as incorporation of bulky group on the nucleobase to prevent the required syn-conformation necessary for proper alignment of N-3 with C-5'.