Sulfonamide-Based Inhibitors of Biotin Protein Ligase as New Antibiotic Leads.

Here, we report the design, synthesis, and evaluation of a series of inhibitors of Staphylococcus aureus BPL (SaBPL), where the central acyl phosphate of the natural intermediate biotinyl-5'-AMP (1) is replaced by a sulfonamide isostere. Acylsulfamide (6) and amino sulfonylurea (7) showed potent in vitro inhibitory activity (Ki = 0.007 ± 0.003 and 0.065 ± 0.03 µM, respectively) and antibacterial activity against S. aureus ATCC49775 with minimum inhibitory concentrations of 0.25 and 4 µg/mL, respectively. Additionally, the bimolecular interactions between the BPL and inhibitors 6 and 7 were defined by X-ray crystallography and molecular dynamics simulations. The high acidity of the sulfonamide linkers of 6 and 7 likely contributes to the enhanced in vitro inhibitory activities by promoting interaction with SaBPL Lys187. Analogues with alkylsulfamide (8), ß-ketosulfonamide (9), and ß-hydroxysulfonamide (10) isosteres were devoid of significant activity. Binding free energy estimation using computational methods suggests deprotonated 6 and 7 to be the best binders, which is consistent with enzyme assay results. Compound 6 was unstable in whole blood, leading to poor pharmacokinetics. Importantly, 7 has a vastly improved pharmacokinetic profile compared to that of 6 presumably due to the enhanced metabolic stability of the sulfonamide linker moiety.

Halogenation of Biotin Protein Ligase Inhibitors Improves Whole Cell Activity against Staphylococcus aureus.

We report the synthesis and evaluation of 5-halogenated-1,2,3-triazoles as inhibitors of biotin protein ligase from Staphylococcus aureus. The halogenated compounds exhibit significantly improved antibacterial activity over their nonhalogenated counterparts. Importantly, the 5-fluoro-1,2,3-triazole compound 4c displays antibacterial activity against S. aureus ATCC49775 with a minimum inhibitory concentration (MIC) of 8 µg/mL.