Figure 4: Amino acid sequence of various plants BZIP domains. The leucine zipper region is divided into heptads (a, b, c, d, e, f, g) to help visualize the g?e’ pairs. Amino acids predicted to regulate dimerization specificity are color coded. If the g and e positions contain charged amino acids, the heptads from g to the following e were colored. Four colors were used to represent g?e’ pairs. Green is used for the attractive basic-acidic pairs (R? E and K? E), orange is for the attaractive acidic-basic pairs (K?R, E?K, D?K), red is for repulsive acidic pairs (E?E and E?D), and blue is for repulsive basic pairs (K?K and R?K). The blue color represents the basic and red for acidic. The prolines and glycines are colored red to indicate potential break in α helical structure. The amino acid leucine is represented in yellow at d position and serine is represented in blue color in the second position of the heptad which interacts with I, N, K and S at the e position. These data indicates that serine contributes less to dimerization specificity than an aliphatic amino acid, polar asparagines or charged lysine residues.