Zinc finger (Znf) domains are relatively small protein motifs which contain multiple finger-like protrusions that make tandem contacts with their target molecule. Some of these domains bind zinc, but many do not; instead binding other metals such as iron, or no metal at all. There are many superfamilies of Znf motifs, varying in both sequence and structure suggesting that this motifs are stable scaffolds that have evolved specialised functions.

Structural domains comprising this superfamily share the structure of the DNA Polymerase alpha zinc finger domain which a helix-turn-helix motif in contrast to other zinc finger domains that show anti-parallel sheet and helix conformation. Zinc binding occurs due to the presence of four cysteine residues positioned to bind the metal centre in a tetrahedral coordination geometry. The function of this domain is uncertain although it has been suggested that this zinc finger motif may be an essential part of the DNA binding domain PMID:14499601.