1GQF image
Deposition Date 2001-11-23
Release Date 2002-01-04
Last Version Date 2023-12-13
Entry Detail
PDB ID:
1GQF
Keywords:
Title:
Crystal structure of human procaspase-7
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.90 Å
R-Value Free:
0.28
R-Value Work:
0.26
R-Value Observed:
0.26
Space Group:
P 32 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Caspase-7
Gene (Uniprot):CASP7
Mutations:C187A
Chain IDs:A, B
Chain Length:265
Number of Molecules:2
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Structural basis for the activation of human procaspase-7.
Proc. Natl. Acad. Sci. U.S.A. 98 14790 14795 (2001)
PMID: 11752425 DOI: 10.1073/pnas.221580098

Abstact

Caspases form a family of proteinases required for the initiation and execution phases of apoptosis. Distinct proapoptotic stimuli lead to activation of the initiator caspases-8 and -9, which in turn activate the common executioner caspases-3 and -7 by proteolytic cleavage. Whereas crystal structures of several active caspases have been reported, no three-dimensional structure of an uncleaved caspase zymogen is available so far. We have determined the 2.9-A crystal structure of recombinant human C285A procaspase-7 and have elucidated the activation mechanism of caspases. The overall fold of the homodimeric procaspase-7 resembles that of the active tetrameric caspase-7. Each monomer is organized in two structured subdomains connected by partially flexible linkers, which asymmetrically occupy and block the central cavity, a typical feature of active caspases. This blockage is incompatible with a functional substrate binding site/active site. After proteolytic cleavage within the flexible linkers, the newly formed chain termini leave the cavity and fold outward to form stable structures. These conformational changes are associated with the formation of an intact active-site cleft. Therefore, this mechanism represents a formerly unknown type of proteinase zymogen activation.

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