Figure 4. Structural determinants of protease substrate specificity based on occurrences at the P6-P6′ positions for cleavage sites.

In each panel, from the left to right, are the assignments at each position for secondary structure (three states: “H”, helix; “E”, strand; “C”, coil), solvent accessibility (two states: “e”, exposed; “b”, buried) and native disorder (two states: “*”, disordered; “.”, ordered), respectively. (A) caspase-1; (B) caspase-3; (C) caspase-7 and (D) caspase-6.