A 966492

Olaparib, AZD-2461, A-966492, niraparib, veliparib, rucaparib, talazoparib, and iniparib were obtained from Selleck and stock solutions (2 mM) were prepared in DMSO. Fluorescent Olaparib (fl-Ola) was obtained from Tocris and a stock solution (10 µM) was prepared in DMSO. The p18mer* DNA oligonucleotides and its complementary strand were obtained from IDT: p18mer: 5′-phosphate-5′-fluorescein-GGGTTGCGGCCGCTTGGG-3′. Nucleosome with overhanging ends of 7 and 11 bp was prepared using the Widom601 sequence as previously described^{40 (link)}. Wild-type PARP1 and PARP2 were expressed and purified as previously described^{41 (link),42} . Purification of HPF1 to homogeneity was performed essentially as previously described^{25 (link)}, with the slight modification of using a gradient for the nickel affinity column from 0 to 40% over 15 CV. The stability of HPF1 was evaluated using the Thermo Fisher Protein Thermal Shift kit according to manufacturer’s instructions.

The PARP inhibitors used in this study were purchased from Selleckchem (Houston, TX, USA) with the following names and catalog numbers: A-966492 (catalog number S2197), AG14361 (catalog number S2178), AZD2461 (catalog number S7029), E7449 (catalog number S8419), G007-LK (catalog number S7239), Niraparib (MK-4827; catalog number S2741), NMS-P118 (catalog number S8363), NU1025 (catalog number S7730), Olaparib (AZD2281, Ku-0059436; catalog number S1060), PJ34-HCl (catalog number S7300), Rucaparib (AG-014699, PF-01367338; catalog number S1098), Talazoparib (BMN673; catalog number S7048), and UPF1069 (catalog number S8038). Stock solutions were dissolved in dimethyl sulfoxide (DMSO) according to the manufacturer’s protocol to a concentration of 10 mM and stored at −20 °C. Table 1 lists the PARP inhibitors used in this study and their proposed targets.