Figure 1.

Structure and function of PARP1. PARP1 contains three functional domains: DNA-binding, auto-modification and catalytic domain. The three zinc fingers are responsible for recognizing aberrances in DNA molecule, followed by binding to it. In the center, the auto-modification domain permits PARylation of PARP itself. Finally, the catalytic domain carries the PARP signature and is responsible for transferring ADP-ribose subunits from nicotinamide adenine dinucleotide (NAD⁺) to PAR onto nuclear acceptor proteins.