The structure of GNF consists of two distorted β-hairpins and an α-helix, with a central zinc atom (green) ligated by four cysteine residues (red). GATA-1 interacts with transcription factors from the FOG family using this N-terminal zinc finger. This interaction is crucial for GATA-1’s ability to correctly regulate gene expression in hematopoetic cells.
This non-native structure corresponds to a fragment of the CH1 domain of CBP. Although the CH1 domain in its native form binds 3 zinc ions (Dames et al, PNAS 2002, 99, 5271-5276), this shorter domain binds only one zinc ion, through a different combination of zinc ligating residues. This novel zinc-binding fold is quite remarkable, given that a sequence, taken out of the context of a whole domain, is able to fold into a stable, yet different structure.