Fig. 2: Cryo-EM structures of CaMKIIα hubs.

a Diagram of the domains of the CaMKIIα hub construct used in this study. b Top view and side view of the cryo-EM maps of the 12-mer (left) and 14-mer (right) AD hubs from the CaMKIIα construct particle numbers (ptcls) used for the map reconstructions are listed. The lateral contact interface and vertical contact interface are indicated with white boxes. c Cryo-EM density and molecular model overlay for the single CaMKIIα AD. The model was colored by Q-score from 0.3 (red) to 0.8 (blue). Average Q-scores for each secondary structure element and for loops are indicated. d Key residues in the vertical contact interface, consisting of a histidine hydrogen bond network. e The lateral contact interface consists of a critical F394–Q436 hydrogen bond and two hydrophobic patches. The two ADs denoted as * and # are colored in pink and purple, respectively. Cryo-EM density and model overlays for the key residues are shown in d and e, with the Q-score for each residue indicated in the brackets.