Structure-Based Design with Arylazopyrazoles to Enable High-Affinity Photoswitchable Inhibitors of N -Myristoyltransferase

Abstract Photopharmacology using photoswitches is a powerful way to reversibly control biological function with light, through the generation of photoswitchable synthetic ligands. While optimization of bioactive small molecules is increasingly driven by iterative experimental protein–ligand structures, structure-guided improvement in photoswitch photopharmacology using experimental structures remains rare. Here we report the development of the first photoswitchable inhibitors of the human enzyme N-myristoyltransferase 1 (HsNMT1), using an arylazopyrazole (AAP) as the switch motif. Through experimental structure-based design, we obtain inhibitors with single-digit nanomolar affinity for NMT, functional activity in cells, and good differential activity between E and Z photoswitch isomers. The availability of our highly potent ligands and protein–ligand structures, coupled with the excellent photoswitch properties of the AAP, allowed us to study the effect of protein binding on the switching events, including characterization of protein-bound Z → E photoisomerization kinetics for the first time. Overall, this study showcases the potential for structure-based design in photoswitch pharmacology, including understanding the dynamic consequences of target binding, paving the way for the development of advanced photopharmaceuticals.