1gef
From Proteopedia
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CRYSTAL STRUCTURE OF THE ARCHAEAL HOLLIDAY JUNCTION RESOLVASE HJC
Overview
BACKGROUND: Homologous recombination is a crucial mechanism in determining, genetic diversity and repairing damaged chromosomes. Holliday junction is, the universal DNA intermediate whose interaction with proteins is one of, the major events in the recombinational process. Hjc is an archaeal, endonuclease, which specifically resolves the junction DNA to produce two, separate recombinant DNA duplexes. The atomic structure of Hjc should, clarify the mechanisms of the specific recognition with Holliday junction, and the catalytic reaction. RESULTS: The crystal structure of Hjc from the, hyperthermophilic archaeon Pyrococcus furiosus has been determined at 2.0, A resolution. The active Hjc molecule forms a homodimer, where an, extensive hydrophobic interface tightly assembles two subunits of a single, compact domain. The folding of the Hjc subunit is clearly different from, any other Holliday junction resolvases thus far known. Instead, it, resembles those of type II restriction endonucleases, including the, configurations of the active site residues, which constitute the canonical, catalytic motifs. The dimeric Hjc molecule displays an extensive basic, surface on one side, which contains many conserved amino acids, including, those in the active site. CONCLUSIONS: The architectural similarity of Hjc, to restriction endonucleases allowed us to construct a putative model of, the complex with Holliday junction. This model accounts for how Hjc, recognizes and resolves the junction DNA in a specific manner. Mutational, and biochemical analyses highlight the importance of some loops and the, amino terminal region in interaction with DNA.
About this Structure
1GEF is a Single protein structure of sequence from Pyrococcus furiosus with SO4 as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of the archaeal holliday junction resolvase Hjc and implications for DNA recognition., Nishino T, Komori K, Tsuchiya D, Ishino Y, Morikawa K, Structure. 2001 Mar 7;9(3):197-204. PMID:11286886
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