Fig. 6: Alternative pathways for open promoter complex formation.
From: Structural basis of ribosomal RNA transcription regulation

Two distinct pathways are shown for open promoter complex formation without (top, blue caption) and with DksA/ppGpp (bottom, red caption). The RNAP holoenzyme (clamp, pink; σNCR, yellow; σ1.1, brown; σ2, orange; βlobe/Si1, light blue; jaw/Si3, purple; rest of RNAP, gray), promoter DNA (tDNA, dark green; ntDNA, light green), DksA (red), and ppGpp (yellow) are shown. Only RPi is a hypothetical intermediate, but others (RPc, RPo, R-DksA, RPc-DksA, RPi-DksA, and RPo-DksA) represent the structures determined in this and previous studies. EC elongation complex.