Fig. 3
From: The essential elements for the noncovalent association of two DNA ends during NHEJ synapsis
XLF increases end proximity of dsDNA within synaptic complexes. a, b Representative single-molecule time traces of donor (green) intensity, acceptor (magenta) intensity, and corresponding EFRET values (blue) for synapsis mediated by 25 nM Ku, 50 nM X4L4, and 50 nM XLF. The right parts are histograms of donor intensity (green), acceptor intensity (magenta), and EFRET values (blue) within synapsis period. c Histogram and corresponding exponential fit of lag time between synapsis starting and transition to high EFRET. Only the events with a detectable transition from low EFRET (E < 0.6) to high EFRET (E ≥ 0.6) were included. n = 23 traces. Error represents the SEM of the fit. d Histogram of EFRET values of all synapsis events mediated by Ku, X4L4, and XLF. The E value shown was obtained from a Gaussian fit of the highest peak of each kind of synaptic complex (FS or CS). n = 423 molecules. The diagram illustrates an end-to-end configuration of the CS state which is ready for ligation. e Histogram and corresponding exponential fit of synapsis time of high EFRET (E ≥ 0.6) events mediated by Ku, X4L4, and XLF. Only the high EFRET events (n = 63) with both start and end time points within the detection time window were included. Error represents the SD of two independent replicates. f XLF concentration-dependent synaptic complex formation. The reaction contains 25 nM Ku, 50 nM X4L4, and varied XLF. FS complex: EFRET < 0.6, CS complex: EFRET ≥ 0.6. Data are represented as mean ± SD of three independent replicates. Source data are provided as a Source Data1 file
