Download MendeleyCrystal structure of a procaspase-7 zymogen: mechanisms of activation and substrate binding
Chai, J., Wu, Q., Shiozaki, E., Srinivasula, S.M., Alnemri, E.S., Shi, Y.(2001) Cell 107: 399-407
- PubMed: 11701129
- DOI: https://doi.org/10.1016/s0092-8674(01)00544-x
- Primary Citation of Related Structures:
1K86, 1K88 - PubMed Abstract:
Apoptosis is primarily executed by active caspases, which are derived from the inactive procaspase zymogens through proteolytic cleavage. Here we report the crystal structures of a caspase zymogen, procaspase-7, and an active caspase-7 without any bound inhibitors. Compared to the inhibitor-bound caspase-7, procaspase-7 zymogen exhibits significant structural differences surrounding the catalytic cleft, which precludes the formation of a productive conformation. Proteolytic cleavage between the large and small subunits allows rearrangement of essential loops in the active site, priming active caspase-7 for inhibitor/substrate binding. Strikingly, binding by inhibitors causes a 180 degrees flipping of the N terminus in the small subunit, which interacts with and stabilizes the catalytic cleft. These analyses reveal the structural mechanisms of caspase activation and demonstrate that the inhibitor/substrate binding is a process of induced fit.
Organizational Affiliation:
Department of Molecular Biology, Lewis Thomas Laboratory, Princeton University, Princeton, NJ 08544, USA.
