Zinc-coordinating DNA-binding domains Nuclear receptors with C4 zinc fingers CLASSLINK:http\://www.edgar-wingender.de/class 2.1.html Class TRANSFAC class description C0002: Zinc finger motif of nuclear receptor type. Two such motifs differing in size, composition and function are present in each receptor molecule. Each finger comprises 4 cysteine residues coordinating one zinc ion. The second half including the second cysteine pair has alpha-helix conformation, the helix of the first finger binds to the DNA through the major groove. The sequence between the first two cysteines of the second finger mediates dimerization upon DNA-binding.