2ZQE: Crystal Structure Of The Smr Domain Of Thermus Thermophilus Muts2

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.
PDB ID: 2ZQEDownload
MMDB ID: 67023
PDB Deposition Date: 2008/8/8
Updated in MMDB: 2008/10
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 2ZQE: monomeric; determined by author and by software (PISA)
Molecular Components in 2ZQE
Label Count Molecule
Protein (1 molecule)
Muts2 Protein(Gene symbol: TTHA1645)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB