Poly [ADP-ribose] polymerase 1 (PARP-1) zinc finger domain (PARP-1 ZnF)

The Poly [ADP-ribose] polymerase 1 (PARP-1) zinc finger domains are critical structural motifs located at the N-terminus of the PARP-1 enzyme that serve as the primary sensors for DNA damage (UniProt P09874). PARP-1 contains three distinct zinc fingers: ZnF1 and ZnF2, which recognize and bind to DNA strand breaks, and ZnF3, which is essential for the allosteric activation of the catalytic domain upon DNA binding (Langelier et al., 2012). In clinical oncology, these domains are central to the mechanism of "PARP trapping," where PARP inhibitors stabilize the enzyme's association with DNA, creating toxic lesions that require homologous recombination for repair (Murai et al., 2012). This trapping effect is a major driver of the synthetic lethality observed in BRCA-mutant cancer cells treated with PARP inhibitors (Lord & Ashworth, 2017). Beyond DNA repair, the zinc finger domains play roles in regulating gene expression and the cellular response to oxidative stress and inflammation (Eustermann et al., 2015). Understanding the structural dynamics of these domains is vital for overcoming drug resistance and developing more potent or selective therapeutic agents.

Other names

PARP1 zinc fingerZnF1/ZnF2/ZnF3 of PARP-1PARP-1 DNA-binding domainZinc finger domain of Poly [ADP-ribose] polymerase 1

PARP inhibitors competitively bind to the NAD+ binding site in the catalytic domain, which prevents the synthesis of poly(ADP-ribose) chains and inhibits the auto-modification of PARP-1 required for its release from DNA. This results in the enzyme being "trapped" on DNA lesions through its zinc finger domains, leading to the collapse of replication forks and the induction of double-strand breaks (Murai et al., 2012; Langelier et al., 2012).