Fig. 6.

A fraction of the immobilized nucleosomes showed dynamics clearly distinct from blinking. a,b After suppression of blinking with Trolox, over 95% of the FRET traces do not show FRET dynamics. The theoretical photon and instrument noise is approximately indicated by the grey bars. c,d ∼3% of the intensity traces (top panels) showed FRET fluctuations (bottom panels) clearly distinct from blinking: the acceptor intensity was significantly higher than zero, and events persisted multiple data points (see insets). These fluctuations clearly exceeded the noise. e Histogram and cumulative distribution plot f of the lifetime of the dynamic events. An exponential fit to the data gave an average lifetime of 120 ms