A few years ago David started to run some experiments with Rhodobacter sphaeroides. We were inspired by prior work by Rick Gourse and Wilma Ross that showed an abundance of unusual promoter elements in this organism. Early on in the project, we had issues reproducing prior observations and, with Rick and Wilma’s help, determined that this was due to differences in DNA supercoiling between our experimental set ups. The project took on a life of its own and this Nature Communications paper is the result.