Mechanistic and Structural Understanding of Uncompetitive Inhibitors of Caspase-6
Figure 6
SPR detection of 3 binding to multiple caspase-6 surfaces confirms uncompetitive binding mode.
(A) Catalytically inactive caspase-6 (green), apo-caspase-6 (blue) and caspase-6 saturated with VEID-FMK inhibitor (purple) were captured to chip surfaces and exposed to VEID-AMC, (VEID)2R110 and/or 3 to qualitatively monitor binding. Cooperative binding of 3 and (VEID)2R110 to C163 caspase-6 illustrate formation of the Michaelis-Menten complex. (B) Sensograms representing injections of escalating concentrations of 3 over VEID-FMK inhibitor-blocked caspase-6 surface (black). The inset represents similar injections of 3 over an unblocked apo-caspase-6 surface (blue). (C) Concentration-response analysis of data from (B) when compound 3 was injected over VEID-blocked caspase-6 surface (black) and apo-caspase-6 (blue) surfaces.