Figure 3.

Stabilities of transcription initiation complexes of T. aquaticus and E. coli RNAPs. The plot shows relative efficiencies of abortive transcription initiation reactions by E. coli and T. aquaticus RNAP holoenzymes at N25cons promoter DNA fragment. All samples were initially incubated for 10 min at optimal (37°C for E. coli and 55°C for T. aquaticus) temperatures. Next, four reactions (1–4) were carried out as following: at the optimal temperatures, either immediately after the initial incubation (1) or after 5 min additional incubation with 50 µg/ml heparin (2). After the initial incubation, samples 3 and 4 were further incubated at 25°C for 15 min, followed by the reactions either without (3) or after the heparin treatment (4).