Notably, forinhibitors causing the strongest compaction, olaparib and talazoparib, (see Fig. 1), exposingPARP1 to these inhibitors before DNA resulted in a 4 and 6-fold reduction, respectively, inthe subsequent binding to DNA, compared with protocols in which PARP1 was allowed tobind to DNA before exposure to inhibitors (Fig. 3B)
I was curious what is known about how PARP1 finds it's nicked DNA target? Is it possible that the reduced binding to the nicked substrate is due to a reduction in the efficiency of finding the substrate (i.e. sliding or inter- or intra-strand transfer?).