Extended Data Fig. 2: Sample preparation and validation of dCMGE cryo-EM reconstructions.

a. Schematic of biochemical reconstitution used for cryo-EM samples. b. Representative cryo-EM micrograph of entire dCMGE assembly reaction with particles highlighted with white circles. Cryo-EM sample preparation was performed once; similar results were observed in at least three independent NS sample preparations. b c. Representative 2D class averages from NS-EM (left panel) and cryo-EM imaging (right panel). Box widths represent 500 Å. d. Fourier shell correlation plot for the C1-refined CMGE dimer map. e. Angular distribution plot for the C1-refined CMGE dimer map. f. CryoSPARC local-resolution estimate for the C1-refined CMGE dimer map. g. Fourier shell correlation plot for symmetry-expanded CMGE map used in model building. h. Angular distribution plot for the symmetry-expanded CMGE map used in model building. i. Model-to-map correlation graph. j. PHENIX local-resolution estimate for the symmetry-expanded CMGE map.