3DEJ

Crystal Structures of Caspase-3 with Bound Isoquinoline-1,3,4-trione Derivative Inhibitors

Summary for 3DEJ

• Entry DOI: 10.2210/pdb3dej/pdb
• Related: 3DEH 3DEI 3DEK
• Descriptor: Caspase-3, (1S)-1-(3-chlorophenyl)-2-oxo-2-[(1,3,4-trioxo-1,2,3,4-tetrahydroisoquinolin-5-yl)amino]ethyl acetate (3 entities in total)
• Functional Keywords: caspase-3, isoquinoline-1, 3, 4-trione derivatives, inactivation, protein-inhibitor complex, apoptosis, cytoplasm, hydrolase, phosphoprotein, polymorphism, protease, s-nitrosylation, thiol protease, zymogen
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P42574
• Total number of polymer chains: 4
• Total formula weight: 114666.77

Authors

Wu, J.,Du, J.,Li, J.,Ding, J. (deposition date: 2008-06-10, release date: 2008-09-02, Last modification date: 2023-11-15)

Primary citation

Du, J.-Q.,Wu, J.,Zhang, H.-J.,Zhang, Y.-H.,Qiu, B.-Y.,Wu, F.,Chen, Y.-H.,Li, J.-Y.,Nan, F.-J.,Ding, J.-P.,Li, J.
Isoquinoline-1,3,4-trione Derivatives Inactivate Caspase-3 by Generation of Reactive Oxygen Species
J.Biol.Chem., 283:30205-30215, 2008

PubMed Abstract: Caspase-3 is an attractive therapeutic target for treatment of diseases involving disregulated apoptosis. We report here the mechanism of caspase-3 inactivation by isoquinoline-1,3,4-trione derivatives. Kinetic analysis indicates the compounds can irreversibly inactivate caspase-3 in a 1,4-dithiothreitol (DTT)- and oxygen-dependent manner, implying that a redox cycle might take place in the inactivation process. Reactive oxygen species detection experiments using a chemical indicator, together with electron spin resonance measurement, suggest that ROS can be generated by reaction of isoquinoline-1,3,4-trione derivatives with DTT. Oxygen-free radical scavenger catalase and superoxide dismutase eliciting the inactivation of caspase-3 by the inhibitors confirm that ROS mediates the inactivation process. Crystal structures of caspase-3 in complexes with isoquinoline-1,3,4-trione derivatives show that the catalytic cysteine is oxidized to sulfonic acid (-SO(3)H) and isoquinoline-1,3,4-trione derivatives are bound at the dimer interface of caspase-3. Further mutagenesis study shows that the binding of the inhibitors with caspase-3 appears to be nonspecific. Isoquinoline-1,3,4-trione derivative-catalyzed caspase-3 inactivation could also be observed when DTT is substituted with dihydrolipoic acid, which exists widely in cells and might play an important role in the in vivo inactivation process in which the inhibitors inactivate caspase-3 in cells and then prevent the cells from apoptosis. These results provide valuable information for further development of small molecular inhibitors against caspase-3 or other oxidation-sensitive proteins.

PubMed: 18768468
DOI: 10.1074/jbc.M803347200

Experimental method

X-RAY DIFFRACTION (2.6 Å)