AraC protein certain to the ara operator works as a repressor that avoid transcription of the same ara operon and the araC gene AraC protein is an activator in the presence of arabinose and repressor in the absence of arabinose -With arabinose absent, the AraC protein stays as
a homodimer. One AraC protein put together to the ara initiator and the other protein now binds to a different regulatory site in DNA called the ara operator.