GeA-69 (GeA69) is a selective and allosteric PARP14 macrodomain 2 (MD2) inhibitor (Kd: 0.86 μM in ITC assays).

PARP14:0.86 μM (Kd, in ITC assays)

Binding experiments were carried out on a VP-ITC microcalorimeter. All experiments were performed in 50 mM HEPES (pH 7.4), 300 mM NaCl, 5 % glycerol, 0.5 mM TCEP at 12 °C, a reference power of 12 μCal/sec and a stirring speed of 307 rpm. The titrations were conducted using an initial injection of 2 μL followed by 28 identical injections of 10 μL with duration of 4 sec (per injection) and a spacing of 240 sec between injections. Competition experiments were performed on an iTC200 instrument at 20 °C, a reference power of 12 μCal/sec and a stirring speed of 1000 rpm. Following an initial injection of 0.2 μL, 20 identical injections of 2 μL were run with a duration of 4 sec (per injection) and a spacing of 150 sec between injections. Data analysis was carried out using Origin software with the MicroCal plugin. Thermodynamic parameters were calculated using ΔG = ΔH ? TΔS = ?RTlnKB, where ΔG, ΔH, and ΔS are the changes in free energy, enthalpy, and entropy of binding, respectively. In all cases, a single binding site model was employed.