text: P  (systematically araBp) is a promoter found in bacteria and especially as part of plasmids used in laboratory studies. The promoter is a part of the arabinose operon whose name derives from the genes it regulates transcription of: araB, araA, and araD. In E. coli, the  P promoter is adjacent to the P promoter (systematically araCp), which transcribes the araC gene in the opposite direction. araC encodes the AraC protein, which regulates activity of both the  P and P promoters. The cyclic AMP receptor protein CAP binds between the  P and P promoters, stimulating transcription of both when bound by cAMP.