Figure 7.

Most TF motifs are centered near either the major or minor groove. Twenty-one yeast TFs are shown as circular dots. Five human TFs are shown as square dots. For each TF, the distance between its motif center and the nearest peak of its motif oscillation is calculated and converted to an “oscillation phase” within [−π/2, π/2]: If the motif center is located at the peak of the composite oscillation and thus tends to be centered on an exposed minor groove, its phase is −π/2; conversely, if the motif center is located at a trough and thus centered on a major groove, its phase is π/2. The y-axis shows the ratio between each TF's motif oscillation amplitude and the amplitude of random oscillations. This is a measure of the significance of the preferential localization. Most TFs have a phase ≥ π/4 or ≤ −π/4 and a ratio >3, indicating that they are significantly associated with the major or minor groove, respectively.