Poly (ADP-ribose) polymerase (PARP) enzymes are a family of proteins involved in a number of cellular processes including gene regulation, chromatin remodeling, DNA repair and apoptosis. These enzymes are present in all eukaryotes except yeast. PARPs can either transfer a single unit of (ADP-ribose) or more than one (ADP-ribose) moieties from NAD(+) onto substrates yielding poly (ADP-ribose) (PAR) chains, which can be of varying length and branch content. The PARP superfamily is composed of 17 members that have a conserved catalytic (CAT) domain (see <PDOC51059>) with various domains like zinc finger (see <PDOC00360>), BRCT (see <PDOC50172>), SAM (see <PDOC50105>), SAP (see <PDOC50800>, ankyrin (see <PDOC50088>) and macro domain (see <PDOC51154>). PARP-1, PARP-2 and PARP-3 are DNA-dependent PARPs that localize to DNA damage, synthesize PAR covalently attached to target proteins including themselves, and thereby recruit repair factors to DNA breaks to increase repair efficiency. PARP-1, PARP-2 and PARP-3 have in common two C-terminal domains, an 80-90 amino acid long tryptophane-, glycine-, arginine-rich (WGR) domain and the CAT domain. The WGR domain participates in binding DNA near the 5' terminus and mediates domain-domain contacts essential for DNA-dependent activity. The CAT domain, which is responsible for binding the substrate NAD(+) and for the synthesis of PAR,contains two subdomains: a helical domain (HD) that is conserved in DNA damage-dependent PARPs 1, 2, and 3, and the ADP-ribosyltransferase (ART) domain that contains the active site and a fold that is conserved in all PARP family members [1,2,3,4,5,6].

WGR binds to the 5'-terminus of one DNA strand, holding the DNA backbone between the central β sheet and the α helix of WGR (see <PDB:4DQY>) [6].

The profile we developed covers the entire WGR domain.