Fig. 7: Model for HelD/δ-mediated RNAP recycling and putative hibernation.
From: The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling
1°/2°, main/secondary channels; RE, RNA exit tunnel; A/G, general elongation factors NusA/NusG. NusG binds across the active center cleft, while NusA binds to the β FT. Semi-transparent icons with dashed lines indicate that the respective factor may be released at the respective step. If the factors remain after termination, NusG will likely be displaced by HelD-induced main channel opening, while the NusA binding site is sequestered in dimeric (RNAP-δ-HelD)2. Hibernation by RNAP-δ-HelD dimerization and ATP-mediated recovery from the dormant state represent tentative aspects of the model.
