文摘
The essential enzyme CYP121 is a target for drug development against antibiotic resistant strains of Mycobacterium tuberculosis. A triazol-1-yl phenol fragment <b>1b> was identified to bind to CYP121 using a cascade of biophysical assays. Synthetic merging and optimization of <b>1b> produced a 100-fold improvement in binding affinity, yielding lead compound <b>2b> (Kb>Db> = 15 μM). Deconstruction of <b>2b> into its component retrofragments allowed the group efficiency of structural motifs to be assessed, the identification of more LE scaffolds for optimization and highlighted binding affinity hotspots. Structure-guided addition of a metal-binding pharmacophore onto LE retrofragment scaffolds produced low nanomolar (Kb>Db> = 15 nM) CYP121 ligands. Elaboration of these compounds to target binding hotspots in the distal active site afforded compounds with excellent selectivity against human drug-metabolizing P450s. Analysis of the factors governing ligand potency and selectivity using X-ray crystallography, UV–vis spectroscopy, and native mass spectrometry provides insight for subsequent drug development.