FIG. 1.

The divergent fuc operons. Shown schematically is the intergenic regulatory region between the fucAO and fucPIK operons. The bent arrow indicates the start point of transcription from the fucPIK promoter (+1). Potential CRP-binding sites are indicated by the rectangles. The sequence of CRP site 1 (hatched rectangle) is shown, as are the three base pair substitutions that were introduced to inactivate this CRP-binding site (vertical arrows). The site of the 1.3-kb IS5 insertion is also indicated (inverted triangle).