Figure 7
rFhKT1.1 binds to the active site groove but not within the active site pockets. Cysteine protease activity in adult F. hepatica excretory/secretory (ES) products measured in the presence of increasing concentrations of cysteine protease inhibitors E-64 (A), Z-Phe-Ala-CHN2 (C) and human cystatin C (E) (% activity, relative to the cysteine protease activity of ES containing no inhibitor ± SD). rFhKT1.1 (10 μM) was added to replicate reaction samples and then pull-down using NTA-beads (B,D,F). In the presence of the low molecular weight inhibitors, E-64 (B) and Z-Phe-Ala-CHN2 (D), rFhKT1.1 (black arrows, B,D) is not prevented from interacting with the cathepsin L cysteine proteases (white arrows, B,D). By contrast, interactions between rFhKT1.1 (black arrow, F) and cathepsin cysteine protease (white arrow, F) are blocked by the recombinant human cystatin C (grey arrow, F) observed by LDS–PAGE. Graphical representations produced using GraphPad Software (v6 for Windows).
