By assembled with their activators/repressors upstream, inducible promoters may detect the existence of inducers such as arabinose and salicylate. The promoters here act as Small Molecule Sensor. Two favourite promoter parts involved have been very well characterized.
(Learn more about the AND GATE AraC+SupD+Sal+RBS(B0033)+T7ptag and Pbad promoter)
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