Fig. 7: Topo II relaxation of chromatin depends on compaction.

a Measurements of topo II relaxation rate on chromatin fibers in different topological states. A chromatin fiber with an active topo II was held for 2 min in each of the following states: the (-‍) buckled state at 50% of its maximal extension, then at the midpoint of the extension plateau regime, then finally in the (+) buckled state at 50% of its maximal extension. The mean rate of topo II in each topological state was calculated from the number of turns relaxed by the bound topo II in the step corresponding to that topological state. b Topo II rate on chromatin fibers as a function of supercoiling state (N = 10 biologically independent traces at each supercoiling state). Both individual data points (gray) as well as their means and SEMs for each topological state (black) are shown. For clarity, the chromatin ActA. Image in 7a is reprinted from ref. ²¹, with permission from Elsevier.