Figure 11. Structure of the DNA binding domain of the human androgen receptor. The protein structure is represented in the one-letter code. The domain consists of two zinc cluster modules, which are stabilized by the coordination binding of a zinc atom (red dot) by 4 cysteine residues (yellow). The first zinc cluster contains the P-box (proximal box), of which three residues determine androgen response element recognition. The second zinc cluster contains the D-box (distal box) in which amino acids are located that are involved in protein-protein interactions with a second receptor molecule in the homodimer complex.