Supplementary Figure 4: Venn diagrams of events obtained and presented.

Venn diagrams of events obtained and presented. The surface of the white box represents the total number (n) of nanomechanical events obtained for each condition. Numbers inscribed within the diagram specify the number of events represented by the delineated surface they are contained within. The surface of the yellow oval represents the number of nanomechanical events for which a flawless nanomechanical trace was obtained over the entire duration of the reaction – i.e. for which 1) there are clearly-detectable transitions in the DNA extension corresponding to well-established transcription events, 2) there is no excessive mechanical drift or noise over ~20-30 minutes, and 3) the intermediate state of a first complex is not interrupted by stochastic loading of a second RNAP¹³. This represents typically upwards of 2/3 of experiments. The surface of the pink oval represents the number of nanomechanical events for which single-molecule fluorescence is concomittantly monitored flawlessly over the lifetime of the object of interest – ie for which 1) the protein or probe turns out to indeed have a functionning fluorophore attached to it, 2) there is no premature photobleaching and 3) fluorescence is not altered by loading of a second fluorecent RNAP. The pink region of this oval and the number inscribed therein corresponds to flawless fluorecent events but corrupted nanomechanical events. The orange region of overlap between yellow and pink ovals corresponds to events presented in this paper, i.e. those events for which there is full monitoring of the process both in the nanomechanical channel and in the fluorescence channel. At the same time all of the data extracted from the partial or interrupted events not part of this orange overlap supports the observations based on data with full coverage in both mechanical and fluorescence channels.