Fig. 4.
Structure of peptide analog inhibitor Ac-LDESD-CHO. 2Fo – Fc electron density map for Ac-LDESD-CHO in one heterodimer of the caspase-3/LDESD complex (a) and caspase-7/LDESD complex (b). The active site cysteine of caspase-3/-7 forms a hemithioacetal bond with the aldehyde group of the inhibitor.