Ferences when compared with the lac operon like the lac acoperon, the ara operon is regulated by glucose levels through the CAP –cAMP complex. However, the AraC regulatory protein the product of the araC gene, exhibits both positive and negative regulatory activity. The AeaC protein in the absence of arabinose binds to specific operators to block RNA polymerase binding and prevent transcriptiom from the pBAD promoter. The distances between the control elements are much greater in yhis operon when compared with the lac operon, and it has been shown the DNA looping occurs after binding of regulatory proteins to bring the elements into luxtaposition to providem the needed interactions. The conformation of the AraC protein changes dramatically in the presence or absence of arabinose