Figure 4.

Comparison of the rate of DNA binding through the monomer and dimer pathways in the presence and absence of excess nonspecific competitor DNA. (A) Scheme illustrating the monomer-binding pathway utilized by Max_22–113 and the covalent dimer pathway utilized by Max_22–105^SS. (B) Phosphorimage illustrating the relative rate of [³²P]Ebox₂₂ binding by Max_22–113 and Max_22–105^SS in the presence or absence of competitor hsEbox_22. The fraction of DNA bound (Θ) by either Max_22–113 (C) or Max_22–105^SS (D) at each time point in the absence (○) or presence (●) of hsEbox₂₂ DNA was normalized to a value of Θ = 1 at equilibrium and fit to a single exponential to give values of k_{no comp} and k_comp, respectively. Each point represented the average of at least four independent experiments. Error bars represent SE.