Fig. 1. Structural and functional overview of EcmrR.
a Activation of in vitro transcription from a synthetic template DNA with a 19-bp promoter spacer by wild-type EcmrR (EcmrR WT) or EcmrR bearing mutations in the cross-subunit NTD-CTD interface (L46A/H50A/Q57A, designated EcmrR M1). The concentrations (in nM) of EcmrR WT and EcmrR M1 are indicated. The experiment was repeated three times and similar results were obtained. RNA products were quantified from these three independent experiments and are shown as mean ± SD. Both of the two distinct RNA bands were quantified, and their signals are combined for plotting. Statistical analyses were performed using the unpaired Student’s t-test (two-tailed). **P < 0.01. b Structure of EcmrR dimer. The model was extracted from the cryo-EM structure of EcmrR-RPo. Cross-subunit NTD-CTD interactions are shown in the dashed box. Interacting residues are shown as sticks. Hydrogen bonds are shown as gray dotted lines. c Schematics of synthetic promoter DNA scaffolds in EcmrR-RPo. The two halves of the palindromic sequence recognized by EcmrR dimer are highlighted by medium blue and orange arrows, respectively. NT-strand, non-template strand; T-strand, template strand. d Cryo-EM map of EcmrR-RPo. The map was generated by merging the consensus map of the full EcmrR-RPo complex and the focused map of EcmrR-spacer DNA subcomplex from EcmrR-RPo (Supplementary Fig. 2) using the Combine Focused Maps tool in Phenix46. e Overall cryo-EM structure of EcmrR-RPo. Three catalytic aspartate residues (β' D460, β' D462 and β' D464) and the Mg2+ ion in the polymerase active center are shown as violet sticks and green sphere, respectively. Source data are provided as a Source Data file.