FIGURE 1.

(A) The data reprocessing includes replicating the density, removing solvent, and normalizing density. (B) The process of coarse-graining cryo-EM data into 12 UCG beads using the CK-CG method. The density map is first divided into 9 blocks. The Hadamard product for each block is obtained by using a Gaussian kernel and the subsequent max-pooling generates the initial positions of 9 UCG beads. The positions of the remaining 3 UCG beads are determined by other maximal densities in the blocks. Then, the 12 positions serve as the centers for clustering to yield the final UCG beads.