Fig. 1: Cryo-EM structure of the RNAP-rrnBP1 closed complex (RPc).
From: Structural basis of ribosomal RNA transcription regulation
a The sequence of the E. coli rrnBP1 promoter DNA used for cryo-EM. The UP element, −35 element, −10 element, transcription start site (TSS, + 1) and discriminator sequence are indicated. Alternative TSS from the nonscrunched open complex is indicated by an asterisk. b Orthogonal views of the RPc cryo-EM density map. Subunits and domains of RNAP and DNA are colored and labeled (βprot, βprotrusion; tDNA, template DNA; ntDNA, nontemplate DNA). The density of downstream DNA beyond the +4 position is not traceable. Blue lines denote the direction of the DNA axis, with kinks at ~−37 and −13. The second DNA at the RNAP cleft is indicated (DNA (2nd)). c A magnified view showing the αCTDs and UP element interaction. The domains of α subunits, σ4, and DNA are depicted as ribbon models with a partially transparent surface. At the top, the sequence of the UP element is shown. The ntDNA (−51 to −48) and tDNA (−54 to −50) sequences binding α1CTD and α2CTD are highlighted in blue and brown, respectively.
