Files in this directory include the interface CA atom coordinates 
extracted from co-crystallized protein complex PDB files. 
They can be used to evaluate docking predictions. The interface is 
defined as all residues with at least one atom located within 10 
angstrom of the other protein. ????_c_r.b.ca includes receptor atoms,
and likewise, ????_c_l.b.ca includes ligand atoms, where ???? stands
for the PDB ID of the complex.
