THE ARABINOSE OPERON: GENES INVOLVED IN ARA OPERON EXPRESSION
The ara operon contains three structural genes: araB, araA, and araD. Because the cell would prefer to utilize glucose instead of arabinose as an energy source, the ara operon contains a CAP-binding site like the one discussed earlier. The operon also contains an inducerbinding site (araI) and an operator-binding site (araO). The organization of the ara operon is shown in figure 16.18. Transcription of the ara operon is controlled by a regulatory protein that is encoded by the araC gene, which is not part of the ara operon.