Structure-guided design and characterization of a clickable, covalent PARP16 inhibitor
Daniel S. Bejan, Sunil K. Sundalam, Haihong Jin, Rory K. Morgan, Ilsa T. Kirby, Ivan Rodriguez Siordia, Barr Tivon, Nir London, Michael S. Cohen
Abstract
other PARP family members. Copper-catalyzed azide-alkyne cycloaddition (CuAAC) confirmed that covalent labeling of PARP16 by DB008 in cells is dependent on Cys169. DB008 exhibits excellent proteome-wide selectivity at concentrations required to achieve saturable labeling of endogenous PARP16. In-cell competition labeling experiments using DB008 provided a facile strategy for evaluating putative PARP16 inhibitors. Lastly, we found that PARP16 is sequestered into a detergent-insoluble fraction under prolonged amino acid starvation, and surprisingly, treatment with PARP16 inhibitors prevented this effect. These results suggest that the catalytic activity of PARP16 regulates its solubility in response to nutrient stress.