Crystal Structure of a mu-like calpain

Experimental Data Snapshot

  • Resolution: 2.80 Å
  • R-Value Free: 0.311 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.233 

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Crystal Structure of a mu-like calpain reveals a partially activated conformation with low Ca(2+) requirement

Pal, G.P.Veyra, T.D.Elce, J.S.Jia, Z.

(2003) Structure 11: 1521-1526

  • DOI: https://doi.org/10.1016/j.str.2003.11.007
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The two Ca2+-dependent cysteine proteases, micro- and m-calpain, are involved in various Ca2+-linked signal pathways but differ markedly in their Ca2+ requirements for activation. We have determined the structure of a micro-like calpain, which has 85% micro-calpain sequence (the first 48 and the last 62 residues of the large subunit are those from m-calpain) and a low Ca2+ requirement. This construct was used because micro-calpain itself is too poorly expressed. The structure of micro-like calpain is very similar in overall fold to that of m-calpain as expected, but differs significantly in two aspects. In comparison with m-calpain, the catalytic triad residues in micro-like calpain, His and Cys, are much closer together in the absence of Ca2+, and significant portions of the Ca2+ binding EF-hand motifs are disordered and more flexible. These structural differences imply that Ca2+-free micro-calpain may represent a partially activated structure, requiring lower Ca2+ concentration to trigger its activation.

  • Organizational Affiliation

    Department of Biochemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
mu-like calpain
A, B
900Rattus norvegicusBos taurusMutation(s): 1 
Find proteins for P97571 (Rattus norvegicus)
Explore P97571 
Go to UniProtKB:  P97571
Find proteins for Q64537 (Rattus norvegicus)
Explore Q64537 
Go to UniProtKB:  Q64537
Find proteins for Q07009 (Rattus norvegicus)
Explore Q07009 
Go to UniProtKB:  Q07009
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsQ64537Q07009P97571
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • R-Value Free: 0.311 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.233 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 72.738α = 90
b = 184.596β = 100.74
c = 86.37γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-02-03
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-08-09
    Changes: Source and taxonomy
  • Version 1.4: 2021-10-27
    Changes: Database references
  • Version 1.5: 2024-02-14
    Changes: Data collection