Structure of human cathepsin B inhibited with ca030. Cathepsin B belongs to the same family as papain, and therefore its fold is representative of the papain-like fold. In this fold, the active site cleft is surrounded by two domains. The N-terminal domain is rich in alpha helices, whereas the C-terminal domain contains a beta barrel. The catalitic site is a catalytic triad with a charge relay system*. This triad includes Cys115, His272, and Asn296. *See family C26 for a more detailed explanation of the charge relay system in a catalytic triad.
Structures are rendered as ribbons. Catalytic and catalytic metal-complexing residues are shown as neons. Inhibitors are displayed as space filling spheres.
Carbons are shown in light gray, hydrogens in cyan, oxygens in red, nitrogens in blue, and sulfurs in yellow.
Left-click and drag to rotate the protease. Right-click and drag up/down to zoom in/out. Click with both buttons and drag to move the protease. Use the upper bar to get different views and for display options. For a close-up of the catalytic site, choose the cat_site view.
Once you have clicked inside the structure window, you can use the keyboard to hide/show objects:
'1' toggles the ribbon. '2' toggles the inhibitor. '3' toggles the catalytic residues.