Extended Data Fig. 2: Cryo-EM data of the S. cerevisiae CCAN–Cenp-ANuc complex.
From: Structure of the inner kinetochore CCAN complex assembled onto a centromeric nucleosome
a, A typical cryo-electron micrograph of CCAN–Cenp-ANuc, representative of 9,002 micrographs. b, Galleries of 2D classes of CCAN, representative of 100 2D classes. c, Galleries of 2D classes of CCAN–Cenp-ANuc, representative of 150 2D classes. The 2D class averages for the C2-symmetric (CCAN)2–Cenp-ANuc complex viewed in the plane of the C2-symmetry axis are outlined in red. Only a few views were observed, precluding a 3D reconstruction. Cryo-EM grids partially destabilize CCAN–Cenp-ANuc interactions, resulting in a very low abundance of (CCAN)2–Cenp-ANuc particles (about 0.03% of total). The two-fold symmetry axes of the (CCAN)2–Cenp-ANuc complex are shown as dashed arrows. Experiments for data in b and c were performed independently 12 times with similar results. d, FSC curves shown for the cryo-EM reconstructions of CCAN–Cenp-ANuc complexes: apo-CCAN, mask1 (Cenp-OPQU+, Cenp-LN), mask2 (Cenp-HIK, Cenp-LN, sub-Cenp-OP), CCAN–Cenp-ANuc. Mask1 and mask2 used for MBR are defined in h and i and Methods. e, Angular distribution plot of CCAN–Cenp-ANuc particles. f, Local resolution map of CCAN. g, Local resolution map of CCAN–Cenp-ANuc. h, Local resolution map of mask1 (Cenp-OPQU+, Cenp-LN). i, Local resolution map of mask2 (Cenp-HIK, Cenp-LN, sub-Cenp-OP).
