Zinc Finger Protein 221 (ZNF221)

ZNF221 belongs to the krueppel C2H2-type zinc-finger protein family. Contains 15 C2H2-type zinc fingers. Contains 1 KRAB domain.Zinc finger protein consists of anti-parallel hairpin motif. It consists of 2 beta strands, one alpha helix and a hairpin structure. The first Zn binds to Cys-3 of 1st beta strand, second Zn binds to Cys-6 that is present in the tight loop that separates the two beta strands. The other two Zn is coordinated to Cys 19 & 23 which are present in C-terminal half of the alpha helix. The hairpin is followed by alpha helix of about 3.5 turns. The ZNF221 binding of Zn at the last two positions mentioned causes distortion in alpha helix between these positions to form a 3-10 complex in which H bonding occurs between 1st and 3rd amino acid instead of 1-4 amino acid bonding. Zn in buried in the interior of the protein and is necessary for the formation of a stable finger structure in aqueous solution.