FIG. 2.

(Left) Representation of the DNA fragments used in the phase-sensitive DNA bending assay. The top pair shows bends in phase and out of phase, and the bottom three show the structures of the three araI sites used. The shaded region is the area in which bases were added to shift the phase of the reference bend with respect to the araI sites. The reference bend was generated by two in-phase A₅ tracts. (Right) Phase-sensitive bend assays of I₁-I₁, I₁-I₂, and I₁-O₂ sites. The distances of migration, in millimeters, are given next to the minimally and maximally retarded species for each construct.