Skip to main content
. 2004 Mar 22;101(14):4776–4780. doi: 10.1073/pnas.0307241101

Fig. 4.

Fig. 4.

Effects of ppGpp, effects of initiating nucleotide, and observation of promoter clearance. (A) Effects of ppGpp (0 or 100 μM) on stability of the unwound complex (consensus promoter, positively supercoiled DNA; σ = 0.018; n = 200 events). (B) Effects of ATP (0 or 2 mM) on stability of the unwound complex (consensus promoter, positively supercoiled DNA; σ = 0.018; n = 100 events). (C) Observation of promoter clearance by detection of successive, cumulative unwinding events, each corresponding to promoter clearance by RNAP molecule n, followed by promoter binding and unwinding by RNAP molecule n + 1 (consensus promoter, positively supercoiled DNA; 2 mM each NTP). (D–F) As in A–C, but for the rrnB P1 promoter, with negatively supercoiled DNA.