Experimental Data Snapshot

  • Resolution: 2.70 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.246 

wwPDB Validation   3D Report Full Report

This is version 1.6 of the entry. See complete history


Investigating the Structural Basis of Purine Specificity in the Structures of MS2 Coat Protein RNA Translational Operator Complexes

Helgstrand, C.Grahn, E.Moss, T.Stonehouse, N.J.Tars, K.Stockley, P.G.Liljas, L.

(2002) Nucleic Acids Res 30: 2678

  • DOI: https://doi.org/10.1093/nar/gkf371
  • Primary Citation of Related Structures:  
    2IZ8, 2IZM, 2IZN

  • PubMed Abstract: 

    We have determined the structures of complexes between the phage MS2 coat protein and variants of the replicase translational operator in order to explore the sequence specificity of the RNA-protein interaction. The 19-nt RNA hairpins studied have substitutions at two positions that have been shown to be important for specific binding. At one of these positions, -10, which is a bulged adenosine (A) in the stem of the wild-type operator hairpin, substitutions were made with guanosine (G), cytidine (C) and two non-native bases, 2-aminopurine (2AP) and inosine (I). At the other position, -7 in the hairpin loop, the native adenine was substituted with a cytidine. Of these, only the G-10, C-10 and C-7 variants showed interpretable density for the RNA hairpin. In spite of large differences in binding affinities, the structures of the variant complexes are very similar to the wild-type operator complex. For G-10 substitutions in hairpin variants that can form bulges at alternative places in the stem, the binding affinity is low and a partly disordered conformation is seen in the electron density maps. The affinity is similar to that of wild-type when the base pairs adjacent to the bulged nucleotide are selected to avoid alternative conformations. Both purines bind in a very similar way in a pocket in the protein. In the C-10 variant, which has very low affinity, the cytidine is partly inserted in the protein pocket rather than intercalated in the RNA stem. Substitution of the wild-type adenosine at position -7 by pyrimidines gives strongly reduced affinities, but the structure of the C-7 complex shows that the base occupies the same position as the A-7 in the wild-type RNA. It is stacked in the RNA and makes no direct contact with the protein.

  • Organizational Affiliation

    Department of Cell and Molecular Biology, Uppsala University, Box 596, SE-751 24 Uppsala, Sweden.


Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Capsid protein
A, B, C
129Escherichia phage MS2Mutation(s): 0 
Gene Names: MS2g2
Find proteins for P03612 (Escherichia phage MS2)
Explore P03612 
Go to UniProtKB:  P03612
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP03612
Sequence Annotations
  • Reference Sequence

Find similar nucleic acids by:  Sequence   |   3D Structure  

Entity ID: 2
MoleculeChains LengthOrganismImage
E [auth S]
19Escherichia phage MS2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.70 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.246 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 288α = 90
b = 288β = 90
c = 653γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-03
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-17
    Changes: Data collection
  • Version 1.4: 2021-04-28
    Changes: Data collection, Other
  • Version 1.5: 2023-03-08
    Changes: Database references, Derived calculations, Other, Refinement description, Source and taxonomy, Structure summary
  • Version 1.6: 2024-03-06
    Changes: Data collection