Fig. 5. Close-up stereoview of the active-site cleft of haemadin-bound human α-thrombin. Side chains of selected residues are depicted colour coded. Intermolecular hydrogen bonds are shown as white dotted lines for the parallel interaction of haemadin’s N-terminal loop with thrombin residues Ser214–Gly216 or yellow dotted lines for contacts made inside the S1 pocket. Some residues of thrombin and the inhibitors along with all water molecules are omitted for the sake of simplicity. The three N-terminal amino acid residues of hirudin (green) are shown for comparison.