Fig. 5

P7 locks RNAP clamp in the closed conformation. a Structural superimposition between Mtb RNAP-Lipiarmycin (PDB: 6FBV) with P7-NusA-TEC shows a 20° swinging of the clamp domain and a concomitant 12-Å movement of β′ZBD from the closed (P7-NusA-TEC) to open (RNAP-LPM) conformation of the clamp domain. b P7 inserts into the RNA exit channel and locks the clamp in the closed-conformation in the structure of P7-NusA-TEC. c The close-up presentation of the P7 binding site with a diameter of 25 Å. d P7 is not compatible with the open-clamp conformation. The P7 outline superposed onto the structure of Mtb RNAP-Lipiarmycin highlights the crushed P7 binding site in the open-clamp conformation. e The 12-Å shift of β′ZBD crushes into the P7 binding site and reduces the P7 binding site to a diameter of 20 Å. f Lipiarmycin (LPM) significantly inhibits the binding of P7 to RNAP, while rifampicin shows no effect in a FP assay. g P7 almost completely inhibits promoter dsDNA binding and isomerization by RNAP in a FP experiment. h P7 has little effect on the binding of pre-melted promoter of RNAP. i P7 inhibits promoter melting in a real-time stopped-flow assay. The experiments were repeated in triplicate, and the data were presented as mean±S.E.M. The source data of Fig. 5f–i are provided in the Source Data file