To determine whether either ydeN or ydeM is required for normal regulation of AraC-activated genes , we constructed a translational fusion of the araE upstream region to lacZ and measured-galactosidase activity in a wildtype strain and in isogenic strains containing deletions of either ydeN or ydeM .
an allosteric change enables AraC to activate the expression of araE
As AraC activates araE transcription , suppression in an AraCˉ background might be caused by a decrease of intracellular L-arabinose due to lack of AraE permease .