Structures of the Human Poly (ADP-Ribose) Glycohydrolase Catalytic Domain Confirm Catalytic Mechanism and Explain Inhibition by ADP-HPD Derivatives

摘要: Poly(ADP-ribose) glycohydrolase (PARG) is the only enzyme known to catalyse hydrolysis of O-glycosidic linkages ADP-ribose polymers, thereby reversing effects poly(ADP-ribose) polymerases. PARG deficiency leads cell death whilst depletion causes sensitisation certain DNA damaging agents, implicating as a potential therapeutic target in several disease areas. Efforts develop small molecule inhibitors activity have until recently been hampered by lack structural information on PARG. We used combination bio-informatic and experimental approaches engineer crystallisable, catalytically active fragment human (hPARG). Here, we present high-resolution structures catalytic domain hPARG unliganded form complex with three inhibitors: (ADPR), adenosine 5′-diphosphate (hydroxymethyl)pyrrolidinediol (ADP-HPD) 8-n-octyl-amino-ADP-HPD. Our confirm conservation overall fold amongst mammalian domains, revealing additional flexible regions site. These new rationalise body published mutational data reported structure-activity relationship for ADP-HPD based inhibitors. In addition, developed biochemical, isothermal titration calorimetry surface plasmon resonance assays characterise binding our protein, thus providing starting point design