Figure 4.

Sample regulation summary diagrams for E. coli . a) The trpD diagram shows inhibition by TrpR (a homodimer, as indicated by the appearance of multiple stacked copies) bound to tryptophan, attenuation by tryptophanyl-tRNA, and substrate-level regulation of the final complex by tryptophan. b) The oppD diagram shows inhibition by several transcription factors (the leucine ligand blocks regulation by Lrp), and regulation of translation by a spermidine riboswitch and RNA GcvB with accessory protein Hfq (a homosexamer). c) The glnG diagram shows activation and dual regulation by several transcription factors, and post-translational modification triggered by phosphorylated NtrB.