FIGURE 3.

A, three P2 molecules (red) placed in three of the 20 possible positions in the P1′247 procapsid based on their fit to the ring-like densities. B, the fit of the P2 structure into the ring-like density from the P1′247 procapsid suggests an orientation and interactions with the three neighboring 5-fold vertices. The main contacts are with the palm (Glu³¹⁶ and Thr⁴⁶⁰), the thumb (Arg⁴⁹ and Phe⁵⁷⁹), and finger (Pro⁵ and Ser³⁸³) domains of the P2 molecule. The substrate pore is directed away from the viewer and toward the 3-fold vertex of the P1 shell. The isosurface was generated at a level of 1 σ.