1EN7

ENDONUCLEASE VII (ENDOVII) FROM PHAGE T4

Summary for 1EN7

• Entry DOI: 10.2210/pdb1en7/pdb
• Descriptor: RECOMBINATION ENDONUCLEASE VII, ZINC ION, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: endonuclease, resolvase, holliday junction, dnase, hydrolase
• Biological source: Enterobacteria phage T4
• Total number of polymer chains: 2
• Total formula weight: 36598.61

Authors

Raaijmakers, H.,Vix, O.,Toro, I.,Suck, D. (deposition date: 1999-02-07, release date: 2000-02-07, Last modification date: 2024-04-03)

Primary citation

Raaijmakers, H.,Vix, O.,Toro, I.,Golz, S.,Kemper, B.,Suck, D.
X-ray structure of T4 endonuclease VII: a DNA junction resolvase with a novel fold and unusual domain-swapped dimer architecture.
EMBO J., 18:1447-1458, 1999

PubMed Abstract: Phage T4 endonuclease VII (Endo VII), the first enzyme shown to resolve Holliday junctions, recognizes a broad spectrum of DNA substrates ranging from branched DNAs to single base mismatches. We have determined the crystal structures of the Ca2+-bound wild-type and the inactive N62D mutant enzymes at 2.4 and 2.1 A, respectively. The Endo VII monomers form an elongated, highly intertwined molecular dimer exhibiting extreme domain swapping. The major dimerization elements are two pairs of antiparallel helices forming a novel 'four-helix cross' motif. The unique monomer fold, almost completely lacking beta-sheet structure and containing a zinc ion tetrahedrally coordinated to four cysteines, does not resemble any of the known junction-resolving enzymes, including the Escherichia coli RuvC and lambda integrase-type recombinases. The S-shaped dimer has two 'binding bays' separated by approximately 25 A which are lined by positively charged residues and contain near their base residues known to be essential for activity. These include Asp40 and Asn62, which function as ligands for the bound calcium ions. A pronounced bipolar charge distribution suggests that branched DNA substrates bind to the positively charged face with the scissile phosphates located near the divalent cations. A model for the complex with a four-way DNA junction is presented.

PubMed: 10075917
DOI: 10.1093/emboj/18.6.1447

Experimental method

X-RAY DIFFRACTION (2.4 Å)