Crystal Structure of Calcium-free Human Sorcin: A Member of the Penta-EF-Hand Protein Family

Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.221 

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Crystal structure of calcium-free human sorcin: a member of the penta-EF-hand protein family.

Xie, X.Dwyer, M.D.Swenson, L.Parker, M.H.Botfield, M.C.

(2001) Protein Sci 10: 2419-2425

  • DOI: https://doi.org/10.1110/ps.36701
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Sorcin is a 22 kD calcium-binding protein that is found in a wide variety of cell types, such as heart, muscle, brain and adrenal medulla. It belongs to the penta-EF-hand (PEF) protein family, which contains five EF-hand motifs that associate with membranes in a calcium-dependent manner. Prototypic members of this family are the calcium-binding domains of calpain, such as calpain dVI. Full-length human sorcin has been crystallized in the absence of calcium and the structure determined at 2.2 A resolution. Apart from an extended N-terminal portion, the sorcin molecule has a globular shape. The C-terminal domain is predominantly alpha-helical, containing eight alpha-helices and connecting loops incorporating five EF hands. Sorcin forms dimers through the association of the unpaired EF5, confirming this as the mode of association in the dimerization of PEF proteins. Comparison with calpain dVI reveals that the general folds of the individual EF-hand motifs are conserved, especially that of EF1, the novel EF-hand motif characteristic of the family. Detailed structural comparisons of sorcin with other members of PEF indicate that the EF-hand pair EF1-EF2 is likely to correspond to the two physiologically relevant calcium-binding sites and that the calcium-induced conformational change may be modest and localized within this pair of EF-hands. Overall, the results derived from the structural observations support the view that, in sorcin, calcium signaling takes place through the first pair of EF-hands.

  • Organizational Affiliation

    Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts 02139-4211, USA. xiaoling_xie@vpharm.com

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
198Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P30626 (Homo sapiens)
Explore P30626 
Go to UniProtKB:  P30626
PHAROS:  P30626
GTEx:  ENSG00000075142 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP30626
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.221 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 118.25α = 90
b = 118.25β = 90
c = 85.49γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2002-01-30 
  • Deposition Author(s): Xie, X.

Revision History  (Full details and data files)

  • Version 1.0: 2002-01-30
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-07
    Changes: Data collection, Database references