Fig. 3
Structural determinants of ApoE self-association. (A) The model of the full-length ApoE3M T-shaped dimer is colored according to the legend, with C112 marked as a blue sphere. (B) Detailed view of helix C1 of chain A located near residues W39, T42, and Q123 (spheres). (C) Superposition of NMR structures of ApoE3M (PDB ID 2L7B; colored according to the legend) and NTD ApoE3 (PDB ID 2KC3; residues 1–23 and 24–165 are shown in pink and grey, respectively). The five “monomerizing” mutations (F257A, W264R, V269A, L279Q, and V287E) in the CTD of ApoE3M are shown as spheres. (D) The structure of truncated ApoEM with marked four mutations (R38A, E45A, E49A, and R145A) was introduced at the self-association interface. (E) Circular dichroism spectra and (F) dynamic light scattering of ApoEM (grey), ApoEM-AP (red), and ApoEM-AS (cyan). The data represent averages of twenty individual repeats. (G) Photo showing soluble ~ transparent ApoEM-AS (left) and an aggregated ~ turbid ApoEM-AP sample two hours after purification (right). Similar results were obtained in at least two independent experiments. (H) TEM of ApoE3M-AP fibrils (red arrows). Similar results were obtained in at least two independent experiments.