FIG. 5.

Analysis of base removal on the coding strand of the E. chrysanthemi EC16 pelE promoter-operator region. (A) DNA molecules were treated with either formic acid to remove G+A or hydrazine to remove C+T and then incubated with KdgR before electrophoresis. DNA isolated from repressor-DNA complexes (lanes C) and DNA that was free of complexes (lanes F) were cleaved by piperidine, electrophoresed, and autoradiographed. (B) Summary of the data obtained by the interference method for the EC16 pelE gene. The magnitude of the effect observed upon removal of a given base is indicated by the size of the bar above (binding interference) or below (enhanced binding) this base; the regions deleted in the modified operators, OP1 and OP2, are underlined.