2FCO: Crystal Structure Of Bacillus Stearothermophilus Prfa-Holliday Junction Resolvase

Citation:
Abstract
Here we report a high resolution structure of RecU-Holliday junction resolvase from Bacillus stearothermophilus. The functional unit of RecU is a homodimer that contains a "mushroom" like structure with a rigid cap and two highly flexible loops extending outwards. These loops appear to be highly flexible/dynamic, and presumably are directly involved in DNA binding and holding it for catalysis. Structural modifications of both the protein and DNA upon their interaction are essential for catalysis. An Mg2+ ion is present in each of the two active sites in this homodimeric enzyme, and two water molecules are coordinated with each Mg2+ ion. Our data are consistent with one of these water molecules acting as a nucleophile and the other as a general acid. The identities of the general base and general acid involved in catalysis and the Lewis acid that stabilizes the pentacovalent transition state phosphate ion are proposed. A model for the RecU-Holliday junction DNA complex is also proposed and discussed in the context of DNA binding and cleavage.
PDB ID: 2FCODownload
MMDB ID: 42752
PDB Deposition Date: 2005/12/12
Updated in MMDB: 2006/12
Experimental Method:
x-ray diffraction
Resolution: 1.4  Å
Source Organism:
Similar Structures:
Biological Unit for 2FCO: dimeric; determined by author
Molecular Components in 2FCO
Label Count Molecule
Proteins (2 molecules)
2
Recombination Protein U (Penicillin-binding Protein Related Factor A)
Molecule annotation
Chemicals (4 molecules)
1
2
2
2
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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