The bend is quite severe, 90 , as illustrated in the model of Figure 10.27. There is therefore a dramatic change in the organization of the DNA double helix when CAP protein binds. The mechanism of bending is to introduce a sharp kink within the TGTGA consensus sequence; the two kinks ...
A topological barrier model in which nucleoprotein complexes confine DNA supercoils to localized regions is consistent with these results25. These results also led us to pose the following questions: Is LacI able to form topological barriers and constrain supercoils in the lac promoter region 1...