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