Extended Data Figure 3 : Three-dimensional reconstruction of CLC-K.

From: Structure of a CLC chloride ion channel by cryo-electron microscopy

Extended Data Figure 3

a, Angular distribution histogram of class 1 particle projections. b, Fourier shell correlation (FSC) of class 1 half maps before (black) and after (blue and red) masking. Two soft masks were used (see also c): one (red) including only the channel portion and the other (blue) including the channel and the variable domain (VH/VL) of the Fab fragments but excluding the constant domain (CH1/CL) of Fab. When a mask was used, the FSC curve was corrected for masking effects during the RELION postprocessing procedure (phase randomization above 7.8 Å). c, Masks used in FSC calculations (red and blue) in b are shown with the unsharpened, unfiltered map (grey) superimposed. A contour level of 0.7 was used for the surface representation of the masks. d, Local resolution map of the class 1 reconstruction estimated by the blocres program. Shown is the combined map, which is not sharpened or filtered. e, FSC between model and map of the class 1 particles. The black curve shows FSC between the final refined atomic model and the combined map that the model was refined against. The blue and red curves show FSC between the atomic model and the half map it was refined against (half 1) and FSC between the atomic model and the other half map it was not refined against (half 2), respectively (see also Methods). fj, As in ae, but with the class 2 structure. For the FSC calculations with the masks in g, the FSC curves were corrected for masking effects (phase randomization above 8.7 Å).