Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Observed: 0.175 

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This is version 1.3 of the entry. See complete history


Structure of calmodulin refined at 2.2 A resolution.

Babu, Y.S.Bugg, C.E.Cook, W.J.

(1988) J Mol Biol 204: 191-204

  • DOI: https://doi.org/10.1016/0022-2836(88)90608-0
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The crystal structure of mammalian calmodulin has been refined at 2.2 A (1 A = 0.1 nm) resolution using a restrained least-squares method. The final crystallographic R-factor, based on 6685 reflections in the range 2.2 A less than or equal to d less than or equal to 5.0 A with intensities exceeding 2.5 sigma, is 0.175. Bond lengths and bond angles in the molecule have root-mean-square deviations from ideal values of 0.016 A and 1.7 degrees, respectively. The refined model includes residues 5 to 147, four Ca2+ and 69 water molecules per molecule of calmodulin. The electron density for residues 1 to 4 and 148 is poorly defined, and they are not included in the model. The molecule is shaped somewhat like a dumbbell, with an overall length of 65 A; the two lobes are connected by a seven-turn alpha-helix. Prominent secondary structural features include seven alpha-helices, four Ca2+-binding loops, and two short, double-stranded antiparallel beta-sheets between pairs of adjacent Ca2+-binding loops. The four Ca2+-binding domains in calmodulin have a typical EF hand conformation (helix-loop-helix) and are similar to those described in other Ca2+-binding proteins. The X-ray structure determination of calmodulin shows a large hydrophobic cleft in each half of the molecule. These hydrophobic regions probably represent the sites of interaction with many of the pharmacological agents known to bind to calmodulin.

  • Organizational Affiliation

    Department of Pathology, University of Alabama, Birmingham 35294.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CALMODULIN148Rattus rattusMutation(s): 0 
Find proteins for P0DP29 (Rattus norvegicus)
Explore P0DP29 
Go to UniProtKB:  P0DP29
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DP29
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Observed: 0.175 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 29.71α = 94.13
b = 53.79β = 97.57
c = 24.99γ = 89.46
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1988-07-16
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other