Extended Data Fig. 7: Conformations of the NTD tier at pH 8.0 and pH 5.5.

a, 3D density map of the GluA2 NTD tier at pH 8.0. Upper panel: top view (BD interface boxed); lower panel: zoom into boxed region. b,c, Representative 3D classes of the NTD and LBD layers at pH 5.5 (b) and pH 8.0 (c). The NTD tiers are marked with dashed boxes. 15 representative classes out of 20 classes total. Particles within each class ranged from 34–90 K (pH 5.5), and 43–90 K (pH 8.0). d, Representative arrangements of the NTD tier at pH 5.5, shown as atomic models from two orthogonal views. Classes 8, 18, 20, 29, 37, and 40 were selected from extensive sub classification of particles into 40 classes (see Methods). The atomic models of the NTD and LBD were rigid-body fitted into the density map.