Figure 1.

Caspase-3 catalytic activity can be allosterically modulated by phosphorylation at Ser¹⁵⁰ or Thr¹⁵². The caspase-3 dimer (Protein Data Bank code 2J30) is illustrated with one protomer shown as a white surface and the other as a light blue surface. Active sites are shown with the Ac-DEVD-CMK inhibitor as colored spheres, with orange carbon atoms. Conformational changes that occur upon phosphorylation of Ser¹⁵⁰ or Thr¹⁵² (colored spheres with blue carbon atoms) are propagated to the active sites through distinct intraprotomer (red bar-headed arrow) or interprotomer (blue bar-headed arrow) pathways.