Fig. 1: Structural overview.
From: The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling
a Overall architecture of an RNAP-δ-HelD complex. β surface is semi-transparent in the upper left panel. Rotation symbols in this and all figures indicate views relative to the upper left panel. Color coding in all figures, unless otherwise noted: α1, dark gray; α2, gray; β, black; β′, light gray; β′ clamp, violet; ε, lime green; δ, slate blue; HelD, red. b Comparison to an E. coli EC (PDB ID 6ALH), illustrating marked widening of the main channel in RNAP-δ-HelD. ω, cyan; template (t) DNA, brown; non-template (nt) DNA, beige; RNA, gold. c Comparison to an E. coli GreB-modified EC (PDB ID 6RIN), illustrating similar secondary channel invasion by coiled-coil elements in GreB and HelD.
