Figure 2.

Reconstruction of the P4 procapsid. (A) Isosurface representation of the icosahedrally symmetric reconstruction, colored radially from the inside (red) to the outside (blue). The triangle represents one icosahedral face (three asymmetric units); the icosahedral symmetry axes are indicated. The schematic diagram shows the arrangement of gpN subunits in the T = 4 lattice. (B) Isosurface representation of the asymmetric reconstruction, viewed as in (A). (C) The atomic model, showing two complete icosahedral asymmetric units, including 8 copies of gpN (A–D and A2–D2) and two copies of Sid. One of the asymmetric units is shown with lighter color. The inset shows the orientation of the model within the capsid. (D) Ribbon diagram showing the entire dodecahedral cage formed by Sid.