Engelsk definition
Zinc finger domains of approximately 50 to 80 amino acids in length that are characterized by a conserved Cysteine(3)-Histidine-Cysteine(4) amino acid motif which coordinates binding of two zinc ions. They are similar structurally to RING FINGER DOMAINS, with a globular fold topology of two BETA-SHEETS and an ALPHA-HELIX. PHD fingers occur in many proteins that function in chromatin-mediated gene expression and EPIGENETICS such as POLYCOMB-GROUP PROTEINS.