In A,it was possible to predict the size of the ligand from the volume of the binding site cleft - the complex between the ligand docosahexaenoic fatty acid and brain lipid-binding protein was modelled on PDB structure 1ADL (62% sequence). In B a binding site for a charged ligand was predicted for mouse mast cell protease 7 based on a cluster of charged residues on the protein. Baker and Sali, Science 2001