Trp repressor Tryptophan Operon Repressor mRNA Leader(trpL) trpA Attenuator trpB trpD trpR P O trpE Structural genes Regulatory region trp mRNA (low tryptophan levels) Attenuated mRNA (high tryptophan levels) Anthranilate Anthranilate Tryptophan Tryptophan synthase, synthase, synthase, synthase, component I component ll B subunit a subunit Anthranilate N-(5'-Phosphoribosyl)- Tryptophan synthase anthranilate isomerase synthase [(Col)2(Coll)2] Indole-3-glycerol (c2P2) phosphate synthase