Figure 2: The shell-based grid force field of protein I of 1AY7. Protein I is shown in blue and protein II in green. Each point represents a force field grid with a 3 Å resolution. Accordingly, for the inner shell (in red) one point corresponds to 6 grids with 0.5 Å resolution; for the outer shell (in orange) one point corresponds to 4 grids with 0.75 Å resolution.