Zinc-binding Motif

The Zinc-Binding Motif

The zinc ion is surrounded by 2 parallel beta sheets and and 2 alpha helices. The zinc ion is bound by 4 cysteine atoms. Three of these are from turns in the backbone of the protein, while one of them is from the recognition helix. This zinc ion helps to hold the protein in the correct conformation to allow the recognition helix to access the major groove and bind to the ERE.