A collaborative study by the UTokyo-KI LINK program, headed by Camilla Björkegren from Karolinska Institutet, Kristian Jeppsson and Katsuhiko Shirahige from The University of Tokyo shows that a protein complex named Smc5/6 binds DNA structures called positive supercoils. These form when the chromosomal DNA double helix folds onto itself due to overtwisting caused by transcription, which is the first step in gene expression.