Figure 3.

Ultra long-lived G4 state. Upper panel shows a long time trace of a telomeric G4 DNA extension fluctuation at ∼5 pN (original and smoothed data are shown in black and red, respectively). In the first 5100 s, stepwise fluctuation with similar kinetics to Figure 2A was observed (red smoothed data for clarity). After 5100 s, the tether extension remained at the folded extension state for 1 h (cyan smoothed data for clarity). Lower panel shows the extension change of the ultra-long lived telomeric G4 being stretched at 2 pN/s, where unfolding occurred at ∼43 pN (the first stretch). After subsequent refolding at 1 pN for 10 s, unfolding occurred at a much lower force of ∼20 pN.