Extended Data Figure 3. Internal consistency and temporal evolution of internal difference map signal.

a–c, Analysis for the data presented in Fig. 3. a, Consistency of estimated signal per residue derived from two data collection passes on the same crystal (black: OFF; blue: 50 ns; green: 100 ns; red: 200 ns). Overall correlation coefficient 0.59. Signal is defined as the integrated absolute difference density above 2.5σ_OFF within 1.5 Å of the protein backbone, square-root transformed to stabilize variance. Per-time-point correlation coefficients are: − 0.07 (OFF, P > 0.1), 0.23 (50 ns; P = 0.01); 0.35 (100 ns; P < 10⁻³) and 0.34 (200 ns; P < 10⁻³). b, Consistency of the obtained signal per residue between time points. Correlation coefficients are: 0.17 (OFF; P = 0.05), 0.55 (50 ns; P = 1 × 10⁻⁹) and 0.72 (100 ns; P < 10⁻²⁰). The diagonal is shown for reference. Note that slight correlation in the OFF data set may indicate imperfect correction for anisotropic absorption. c, Signal integrated along the entire protein backbone in passes 1 and 2 (blue crosses and circles, respectively) and over the entire data set (squares). The red line indicates a naive expectation of a $\sqrt{2}$-fold increase in signal-to-noise ratio.