In vitro inhibition of transcription catalyzed by T. aquaticus RNAP by streptolydigin derivatives. A. A comparison of RNAP inhibitory activity of streptolydigin (1), 10,11-dihydrostreptolydigin (63), and adamantane derivative 56 using 10 µM NTP and 0.1 mM of each inhibitor. B. Dose-dependent RNAP inhibition by streptolydigin (1), streptolydiginone (4) and 10,11-dihydrostreptolydigin (63). C. Quantitative assessment of inhibitory effects of streptolydigin (1), streptolydiginone (4) and 10,11-dihydrostreptolydigin (63) on the rate of CMP incorporation into nascent 8-nt starting RNA.