Figure 2a.

Plastocyanin (white tubes with gold sphere for the bound copper ion) surrounded by spheres representing centers of the 2,000 most favorable configurations of cytochrome c found by DOT. In this energy evaluation, only the configuration with the best energy for each grid point was saved. A blue sphere indicates a more favorable energy (larger negative number) than a red one. A single cluster of spheres is seen, agreeing with the results from TURNIP, in which cytochrome c was found to approach the face of plastocyanin that contains the tyrosine 83 side chain (red ring). A view of a larger volume can be seen in Figure 2b.