Crystal structure of the Smr domain of Thermus thermophilus MutS2

Experimental Data Snapshot

  • Resolution: 1.70 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 

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Crystal structure of MutS2 endonuclease domain and the mechanism of homologous recombination suppression

Fukui, K.Nakagawa, N.Kitamura, Y.Nishida, Y.Masui, R.Kuramitsu, S.

(2008) J Biol Chem 283: 33417-33427

  • DOI: https://doi.org/10.1074/jbc.M806755200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    DNA recombination events need to be strictly regulated, because an increase in the recombinational frequency causes unfavorable alteration of genetic information. Recent studies revealed the existence of a novel anti-recombination enzyme, MutS2. However, the mechanism by which MutS2 inhibits homologous recombination has been unknown. Previously, we found that Thermus thermophilus MutS2 (ttMutS2) harbors an endonuclease activity and that this activity is confined to the C-terminal domain, whose amino acid sequence is widely conserved in a variety of proteins with unknown function from almost all organisms ranging from bacteria to man. In this study, we determined the crystal structure of the ttMutS2 endonuclease domain at 1.7-angstroms resolution, which resembles the structure of the DNase I-like catalytic domain of Escherichia coli RNase E, a sequence-nonspecific endonuclease. The N-terminal domain of ttMutS2, however, recognized branched DNA structures, including the Holliday junction and D-loop structure, a primary intermediate in homologous recombination. The full-length of ttMutS2 digested the branched DNA structures at the junction. These results indicate that ttMutS2 suppresses homologous recombination through a novel mechanism involving resolution of early intermediates.

  • Organizational Affiliation

    RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo-gun, Hyogo, 679-5148, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MutS2 protein83Thermus thermophilus HB8Mutation(s): 0 
Gene Names: TTHA1645
Find proteins for Q5SHT5 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8))
Explore Q5SHT5 
Go to UniProtKB:  Q5SHT5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ5SHT5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.70 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.191 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.813α = 90
b = 54.216β = 90
c = 30.243γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-09-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 1.2: 2023-11-01
    Changes: Data collection, Database references, Refinement description