Experimental Data Snapshot

  • Resolution: 1.30 Å
  • R-Value Observed: 0.176 

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This is version 1.4 of the entry. See complete history


Refinement of recombinant oncomodulin at 1.30 A resolution.

Ahmed, F.R.Rose, D.R.Evans, S.V.Pippy, M.E.To, R.

(1993) J Mol Biol 230: 1216-1224

  • DOI: https://doi.org/10.1006/jmbi.1993.1237
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A refinement of the oncomodulin crystal structure at 1.30 A resolution has been carried out with X-ray data from the recombinant protein. The crystallographic R-factor values are 0.169 for 19,995 reflections in the range 6.0 to 1.30 A, which were used for the restrained least-squares refinement, and 0.176 for 20,186 observed reflections in the range 10.0 to 1.30 A. This high resolution refinement has enabled us to make more definitive statements about the molecular structure than was possible heretofore. The present model includes residues 1 to 108, the two Ca2+ of the CD and EF loops, two intermolecular Ca2+, and 103 water molecules per oncomodulin molecule. The electron density maps indicate disordered orientations for ten residues on the hydrophilic surface of the molecule. The pattern of molecular aggregation via intermolecular Ca2+, which occurs in the native rat oncomodulin structure, is also present in the recombinant oncomodulin structure. The Cys18 side-chain is not in a position that would be easily accessible for molecular dimerization via a disulphide bond. The substitution of Glu59, which is preserved in all the determined species of parvalbumin, by Asp59 in oncomodulin seems to break a stabilizing hydrogen bond in the CD loop and render the main-chain in positions 59 to 60 somewhat unstable. This instability in the CD loop, and the strong tendency of oncomodulin for molecular aggregation via intermolecular Ca2+, appear to be the two outstanding features that may account for oncomodulin's biological peculiarities.

  • Organizational Affiliation

    Institute for Biological Sciences, National Research Council of Canada, Ottawa.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
RAT ONCOMODULIN108Rattus rattusMutation(s): 0 
Find proteins for P02631 (Rattus norvegicus)
Explore P02631 
Go to UniProtKB:  P02631
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02631
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.30 Å
  • R-Value Observed: 0.176 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 39.7α = 90
b = 65.12β = 90
c = 32.94γ = 90
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: 2017-11-29
    Changes: Derived calculations, Other
  • Version 1.4: 2024-02-14
    Changes: Data collection, Database references, Derived calculations