FIGURE 1.

Highlighting key sites on the serine protease thrombin. The catalytic triad, the anion-binding exosites, and the autolysis loop are marked in black. The catalytic triad is represented by Ser¹⁹⁵, His⁵⁷, and Asp¹⁰² and shown as sticks. The anion-binding exosites of thrombin (ABE I and ABE II) are located at opposite sides of the active site and are shown as sticks. The Protein Data Bank code was 1PPB. The figure was prepared with PyMOL.