The Role of Loop Bundle Hydrogen Bonds in the Maturation and Activity of(Pro)caspase-3

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 

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Role of Loop Bundle Hydrogen Bonds in the Maturation and Activity of (Pro)Caspase-3.

Feeney, B.Pop, C.Swartz, P.Mattos, C.Clark, A.C.

(2006) Biochemistry 45: 13249

  • DOI: https://doi.org/10.1021/bi0611964
  • Primary Citation of Related Structures:  
    2J30, 2J31, 2J32, 2J33

  • PubMed Abstract: 

    During maturation, procaspase-3 is cleaved at D175, which resides in a linker that connects the large and small subunits. The intersubunit linker also connects two active site loops that rearrange following cleavage and, in part, form the so-called loop bundle. As a result of chain cleavage, new hydrogen bonds and van der Waals contacts form among three active site loops. The new interactions are predicted to stabilize the active site. One unresolved issue is the extent to which the loop bundle residues also stabilize the procaspase active site. We examined the effects of replacing four loop bundle residues (E167, D169, E173, and Y203) on the biochemical and structural properties of the (pro)caspase. We show that replacing the residues affects the activity of the procaspase as well as the mature caspase, with D169A and E167A replacements having the largest effects. Replacement of D169 prevents caspase-3 autoactivation, and its cleavage at D175 no longer leads to an active enzyme. In addition, the E173A mutation, when coupled to a second mutation in the procaspase, D175A, may alter the substrate specificity of the procaspase. The mutations affected the active site environment as assessed by changes in fluorescence emission, accessibility to quencher, and cleavage by either trypsin or V8 proteases. High-resolution X-ray crystallographic structures of E167A, D173A, and Y203F caspases show that changes in the active site environment may be due to the increased flexibility of several residues in the N-terminus of the small subunit. Overall, the results show that these residues are important for stabilizing the procaspase active site as well as that of the mature caspase.

  • Organizational Affiliation

    Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CASPASE-3250Homo sapiensMutation(s): 1 
Gene Names: CASP3CPP32
UniProt & NIH Common Fund Data Resources
Find proteins for P42574 (Homo sapiens)
Explore P42574 
Go to UniProtKB:  P42574
GTEx:  ENSG00000164305 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP42574
Sequence Annotations
  • Reference Sequence

Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Sequence Annotations
  • Reference Sequence
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.200 
  • Space Group: I 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.332α = 90
b = 83.925β = 90
c = 95.504γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-11-08
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance
  • Version 1.2: 2013-03-06
    Changes: Other
  • Version 1.3: 2016-12-21
    Changes: Source and taxonomy
  • Version 1.4: 2019-05-08
    Changes: Data collection, Derived calculations, Experimental preparation, Other