Experimental Data Snapshot

  • Resolution: 1.70 Å
  • R-Value Observed: 0.216 

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This is version 1.3 of the entry. See complete history


Calmodulin structure refined at 1.7 A resolution.

Chattopadhyaya, R.Meador, W.E.Means, A.R.Quiocho, F.A.

(1992) J Mol Biol 228: 1177-1192

  • DOI: https://doi.org/10.1016/0022-2836(92)90324-d
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We have determined and refined the crystal structure of a recombinant calmodulin at 1.7 A resolution. The structure was determined by molecular replacement, using the 2.2 A published native bovine brain structure as the starting model. The final crystallographic R-factor, using 14,469 reflections in the 10.0 to 1.7 A range with structure factors exceeding 0.5 sigma, is 0.216. Bond lengths and bond angle distances have root-mean-square deviations from ideal values of 0.009 A and 0.032 A, respectively. The final model consists of 1279 non-hydrogen atoms, including four calcium ions, 1130 protein atoms, including three Asp118 side-chain atoms in double conformation, 139 water molecules and one ethanol molecule. The electron densities for residues 1 to 4 and 148 of calmodulin are poorly defined, and not included in our model, except for main-chain atoms of residue 4. The calmodulin structure from our crystals is very similar to the earlier 2.2 A structure described by Babu and coworkers with a root-mean-square deviation of 0.36 A. Calmodulin remains a dumb-bell-shaped molecule, with similar lobes and connected by a central alpha-helix. Each lobe contains three alpha-helices and two Ca2+ binding EF hand loops, with a short antiparallel beta-sheet between adjacent EF hand loops and one non-EF hand loop. There are some differences in the structure of the central helix. The crystal packing is extensively studied, and facile crystal growth along the z-axis of the triclinic crystals is explained. Herein, we describe hydrogen bonding in the various secondary structure elements and hydration of calmodulin.

  • Organizational Affiliation

    Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CALMODULIN148Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P0DP23 (Homo sapiens)
Explore P0DP23 
Go to UniProtKB:  P0DP23
GTEx:  ENSG00000198668 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DP23
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.70 Å
  • R-Value Observed: 0.216 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 30.17α = 93.62
b = 53.6β = 97.3
c = 25.14γ = 89.17
Software Package:
Software NamePurpose

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-24
    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, Derived calculations