Figure 4.

Amino acid residues and base pairs that influence DNA bending by Fos and Jun. The positions of the amino acid residues that induce DNA bending by Fos (red) and Jun (blue) are shown as dot surfaces based on the x-ray crystal structure. The α-helix of Jun was extended by three residues to indicate the approximate positions of residues for which no density was detected in the x-ray crystallographic analysis. Sequences flanking the AP-1 site and the single base pair at position −6 that influence the DNA bend angle are shown in orange and purple respectively. The charged phosphate oxygens are shown as green dot surfaces. The charge interactions predicted to induce DNA bending are shown in white, with an arrow indicating the direction of DNA bending. The conserved arginine in Fos and the central base pair that influence the orientation of heterodimer binding are shown in red.