Crystallographic structure of calcium loaded Calbindin-D28K.

Experimental Data Snapshot

  • Resolution: 1.51 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.203 

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The X-ray structure of human calbindin-D28K: an improved model.

Noble, J.W.Almalki, R.Roe, S.M.Wagner, A.Duman, R.Atack, J.R.

(2018) Acta Crystallogr D Struct Biol 74: 1008-1014

  • DOI: https://doi.org/10.1107/S2059798318011610
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Calbindin-D28K is a widely expressed calcium-buffering cytoplasmic protein that is involved in many physiological processes. It has been shown to interact with other proteins, suggesting a role as a calcium sensor. Many of the targets of calbindin-D28K are of therapeutic interest: for example, inositol monophosphatase, the putative target of lithium therapy in bipolar disorder. Presented here is the first crystal structure of human calbindin-D28K. There are significant deviations in the tertiary structure when compared with the NMR structure of rat calbindin-D28K (PDB entry 2g9b), despite 98% sequence identity. Small-angle X-ray scattering (SAXS) indicates that the crystal structure better predicts the properties of calbindin-D28K in solution compared with the NMR structure. Here, the first direct visualization of the calcium-binding properties of calbindin-D28K is presented. Four of the six EF-hands that make up the secondary structure of the protein contain a calcium-binding site. Two distinct conformations of the N-terminal EF-hand calcium-binding site were identified using long-wavelength calcium single-wavelength anomalous dispersion (SAD). This flexible region has previously been recognized as a protein-protein interaction interface. SAXS data collected in both the presence and absence of calcium indicate that there are no large structural differences in the globular structure of calbindin-D28K between the calcium-loaded and unloaded proteins.

  • Organizational Affiliation

    School Of Life Sciences, University Of Sussex, Falmer, Brighton BN1 9QG, England.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CalbindinA [auth B]264Homo sapiensMutation(s): 0 
Gene Names: CALB1CAB27
UniProt & NIH Common Fund Data Resources
Find proteins for P05937 (Homo sapiens)
Explore P05937 
Go to UniProtKB:  P05937
GTEx:  ENSG00000104327 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP05937
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.51 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.203 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.617α = 90
b = 104.222β = 90
c = 29.614γ = 90
Software Package:
Software NamePurpose
AutoPROCdata scaling
BUCCANEERmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Biotechnology and Biological Sciences Research CouncilUnited Kingdom--

Revision History  (Full details and data files)

  • Version 1.0: 2018-10-10
    Type: Initial release
  • Version 1.1: 2018-10-17
    Changes: Data collection, Database references