Fig. 3
Magnetic tweezers assay reveals target capture dynamics. a A typical field of view depicting ~50 beads used for tracking (yellow) and reference beads (blue). b DNA tethers are supercoiled using external magnets and exhibit extension fluctuations with SD σz. Target capture reduces σz via DNA bridging. Transient interface unbinding repositions intasomes thereby affecting extension. c Time trace of supercoiled target DNA extension before and after binding A188D CI intasomes (blue: raw data at 58 Hz, yellow: 1 Hz smoothed data). d Enlarged region of c highlighting the onset of dynamic bridging (green dotted line) and coinciding σz reduction calculated with a 0.5 s moving window (red lines: trace fitted using step-finding algorithm)24. e Exponential fit of ΔtTCCA188D distribution yields a lifetime of auxiliary interfaces τTCCA188D = 3.0 ± 0.5 s. (Error is 95% CI; n = 724). f Time trace of supercoiled DNA extension and response to binding WT CI in Ca2+ buffer. g Enlarged region of f shows the onset of dynamic bridging and σz reduction (green dotted line). h Exponential fit of ΔtTCCCa2+ distribution with lifetime τTCCCa2+ = 6.9 ± 1.3 s. (Error is 95% CI; n = 750). Source data are provided as a Source Data file
