Catbolite Activator Protein     a homodimer that binds    cAMP increasing the    protein's affinity for DNA    enhancing    RNA polymerase's ability    to transcribe the structural    genes of the LAC Operon
	The CAP DNA binding domain is a helix-turn-helix motif that binds to major groove of DNA, opening it thus allowing RNA polymerase to bind and transcribe LAC Operon genes.