|
Figure 5.
Key structural elements of caspase-1 dimer stabilization. A,
schematic representation of caspase-1 zymogen (left, PDB code
3E4C) and processed ligand-free caspase-1 (right, PDB code 1SC1
(42)). The proenzyme shows a well defined α-helix near the
putative N terminus of the p10. This element contains cleavage
Site 2, which is the critical processing site for caspase-1
activation. Once proteolysis occurs at Asp^316, the newly formed
p20 C terminus and p10 N terminus are able to form anti-parallel
β-sheets in the active enzyme. The important secondary
structural elements are indicated with red circles. B, diagram
of the backbone atoms of residues 314-321. Brackets indicate
backbone interactions in the α-helix in the proenzyme
structure. Two of the three hydrogen bonds in the helix are
severed upon proteolysis at Asp^316, indicated with an arrow.
|
