Initial transcription by S. oneidensis RNAP involves scrunching of promoter DNA. (A) Derivative of lacCONS promoter utilized to monitor the contraction of DNA between positions −15 (Cy3B, as donor) and +15 (Alexa647, as acceptor). The promoter −35 and −10 elements are grey-colored, as is the start site, which is boxed and indicated with an arrow. (B) Left, schematic of DNA scrunching by RNAP. Right, two representative E* histograms compromising of the free DNA (lowest E* value, solid black line), RPo (dashed black line) or RPitc,≤ 7 (higher E* values, corresponding to DNA bending by the RNAP, solid red line).