PMID: 22233320
Narwal M, Venkannagari H, Lehtio L
Structural Basis of Selective Inhibition of Human Tankyrases.
J Med Chem. 2012 Jan 10.
Tankyrases are poly(ADP-ribose) polymerases that have many cellular functions. They play pharmaceutically important roles, at least in telomere homeostasis and Wnt signaling, by covalently ADP-ribosylating target proteins and consequently regulating their functions. These features make tankyrases potential targets for treatment of cancer. We report here crystal structures of human tankyrase 2 catalytic fragment in complex with a by-product, nicotinamide and with selective inhibitors of tankyrases (IWR-1) and PARPs 1 and 2 (olaparib). Binding of these inhibitors to tankyrase 2 induce specific conformational changes. The crystal structures explain the selectivity of the inhibitors, reveal the flexibility of a substrate binding loop and explain existing structure-activity relationship data. The first crystal structure of a PARP enzyme in complex with a potent inhibitor, IWR-1, which does not bind to the widely-utilized nicotinamide-binding site makes the structure valuable also for development of PARP inhibitors in general.