The zf-AD domain, also known as ZAD, forms an atypical treble-cleft-like zinc co-ordinating fold. The zf-AD domain is thought to be involved in mediating dimer formation, but does not bind to DNA [1].

1: The zinc finger-associated domain of the Drosophila transcription factor grauzone is a novel zinc-coordinating protein-protein interaction module. Jauch R, Bourenkov GP, Chung HR, Urlaub H, Reidt U, Jackle H, Wahl MC; Structure. 2003;11:1393-1402. PMID:14604529