Figure 4.

Circular permutation assay. Alteration of DNA conformation by HMG1+2 factor determined by circular permutation assay. (A) Multiple digestions of cloned HMG1+2 motif in the pBend2 (see Fig. 1D) produced probes of equal length bounded by the indicated restriction enzyme sites. The open box indicates the location of the HMG1+2 motif along each probe. (B) Resolution of various probes on 4% polyacrylamide gel after incubation with purified HMG1+2 factor. The mobilities of the fastest (lane 1) and slowest (lane 3) DNA–protein complexes were used to estimate a DNA bending angle (α) of 54° as described in Materials and Methods.