A model of the active site of human CLN2. The enzyme is shown in complex with pseudo-iodotyrostatin, a good inhibitor of the sedolisin family of peptidases. Only selected residues of the enzyme are explicitly shown on the background consisting of the molecular surface. The stick model of the inhibitor is colored gold and the P1-P3 residues are labeled in black. Similar views have been previously published for the experimentally-determined structures of sedolisin and kumamolisin . The figure was prepared using the program DINO http://www.bioz.unibas.ch/~xray/dino.