... arepresentative of thyropins [29], chagasin [30,31] andmycocypins [32].The N-terminal trunk comes down the S1 bindingarea of cathepsin B, occupies the S2 binding site withproline residue P3, and continues ... additionalfeatures of the exopeptidases, occluding loop and minichain, which occupy parts of the active site cleft(Fig. 2). These additional features hinder binding alongthe whole interdomain interface, ... shift of the occlud-ing loop is related to the size of the binding region. It is smallest in theprocathepsin structures and increases in the series of complexes with stefinA and chagasin, although...