NMR Solution Structure of the Calcium-binding Domain of Nucleobindin (CALNUC)

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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This is version 1.4 of the entry. See complete history


Structural Studies on the Ca(2+)-binding Domain of Human Nucleobindin (Calnuc).

De Alba, E.Tjandra, N.

(2004) Biochemistry 43: 10039-10049

  • DOI: https://doi.org/10.1021/bi049310a
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Nucleobindin, also known as calnuc, participates in Ca2+ storage in the Golgi, as well as in other biological processes that involve DNA-binding and protein-protein interactions. We have determined the three-dimensional solution structure of the Ca(2+)-binding domain of nucleobindin by NMR showing that it consists of two EF-hand motifs. The NMR structure indicates that the phi and psi angles of residues in both motifs are very similar, despite the noncanonical sequence of the C-terminal EF-hand, which contains an arginine residue instead of the typical glycine at the sixth position of the 12-residue loop. The relative orientation of the alpha-helices in the N-terminal EF-hand falls within the common arrangement found in most EF-hand structures. In contrast, the noncanonical EF-hand deviates from the average orientation. The two helix-loop-helix moieties are in the open conformation characteristic of the Ca(2+)-bound state. We find that both motifs bind Ca2+ with apparent dissociation constants of 47 and 40 microM for the noncanonical and the canonical EF-hand, respectively. The Ca(2+)-binding domain of nucleobindin is unstructured in the absence of Ca2+ and folds upon Ca2+ addition. NMR relaxation data and structural studies of the folded domain indicate that it undergoes slow dynamics, suggesting that it is floppier and less compact than a globular domain.

  • Organizational Affiliation

    Laboratory of Biophysical Chemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 Center Drive, Bethesda, Maryland 20892, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nucleobindin 1103Homo sapiensMutation(s): 0 
Gene Names: NUCB1NUC
UniProt & NIH Common Fund Data Resources
Find proteins for Q02818 (Homo sapiens)
Explore Q02818 
Go to UniProtKB:  Q02818
PHAROS:  Q02818
GTEx:  ENSG00000104805 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ02818
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-08-17
    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: 2022-03-02
    Changes: Data collection, Database references, Derived calculations
  • Version 1.4: 2024-05-22
    Changes: Data collection