Computer models of the ER DBD from X-ray crystallographic structure determination (PDB structure ID: 1HCQ) docked at a 25bp DNA sequence from Genebank locus XLVIT15 (see figure 2c). Amino acid and codon alignments are highlighted on the protein and DNA respectively. All highlighted residues have a dot surface indicating the van der Waals surfaces of each atom in that residue. The DNA nucleotides are color coded: Ade = green, Thy = red, Gua = yellow and Cyt = blue. Color coding of amino acids is based on polarity: positively charged side chains = blue, negatively charged side chains = red, uncharged polar side chains = yellow and nonpolar side chains = purple. The protein is docked at a distance of about 10 angstroms from the DNA for visual clarity.

a. Lysine residues from the exon 2 encoded DNA recognition helix (K206 and K210) and lysine codons in the DNA are highlighted. Amino acids are numbered as in human ER (37).
b. Exon 2 encoded DNA recognition helix phenylalanine (F208) residues and phenylalanine codons are highlighted.

c. Serine residues from the exon 2 encoded DNA recognition helix (S212) and serine codons are highlighted.
d. Glutamine residues from the exon 2 encoded DNA recognition helix (Q214) and exon 3 encoded beta strand (Q238) and glutamine codons are highlighted.

e. Exon 3 encoded beta strand histidine residues (H216) and histidine codons are highlighted.
f. Exon 3 encoded beta strand aspartic acid residues (D218) and aspartic acid codons are highlighted.