Fig. 1. Ligand-triggered crystal lattice transition observed by PVM.

a Video microscopy images of an “ab” (c-axis along the thin edge) riboA crystal before (top left) and after (top right) the phase transition in the presence of 1 mM ligand. The yellow box defines the ~4.5 µm square (180 × 180 = 32,400 pixels) region of interest (ROI) used for the detailed analysis. The crystal is continuously monitored at the pixel level, starting from the beginning (bottom left) to the end (bottom right). A 30 × 30 pixels square area in the yellow box is used to show the crystal is birefringent at the pixel level before (bottom left) and after (bottom right) the transition. The images are color-enhanced for clear visualization of individual pixels and the nonuniform crystal surface. b Intensity I_i[(xy)_it] (arbitrary units) vs. time trace (in s) for the single-center pixel of the ROI. Black dots represent the intensities of individual pixels, and the red line is a time average of the derivative with a smoothing window of 15.2 s (left). Derivative −∂I_i[(xy)_it)]/∂t vs. time so that peaks represent the maximum rate of intensity decrease (right). Black dots represent the instantaneous derivative at each time point. The red line is a time average of the derivative with a smoothing window of 7.78 s. c Bivariate histogram of peak half-width of transitions 1, 2, and 3 (T1, T2a and b, and T3) (y-axis) and transition time (x-axis) for all (32,400) pixels in the ROI. d Transition time vs. size of sampling areas. Time zero in the PVM experiment refers to the first frame (200) used in the digitization. Source data are provided as a Source Data file.