FIG. 2.

Three-dimensional reconstruction of HFV spike glycoproteins. The reconstruction was performed with 626 images of negatively stained HFV Env trimers in hexagonal clusters by using a model-based, iterative approach. The top row of the figure shows the averaged particle images (A, B, C, and D) corresponding to the projections (E, F, G, and H) of the reconstruction shown in the middle row. The bottom row shows surface representations of the reconstruction (I, J, K, and L) contoured at a volume which corresponds to that expected for four Env trimers. The four views displayed are at the following orientations of θ, ϕ: 0°, 0° (A, E, and I), 90°, 0° (B, F, and J), 45°, 30° (C, G, and K), and 30°, 180° (D, H, and L), where the z axis (θ, ϕ = 0°, 0°) lies along the threefold axis. The bar represents 10 nm.