2qnf

Crystal structure of T4 Endonuclease VII H43N mutant in complex with heteroduplex DNA containing base mismatches

spinqualitylabelsall models 2qnf, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2qnf is a 6 chain structure with sequence from Escherichia virus T4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3Å Ligands: ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function END7_BPT4 Cleaves DNA cruciform and Y-structures as well as heteroduplex loops. Resolves Holliday junctions, recognizes a broad spectrum of DNA substrates ranging from branched DNAs to single base mismatches. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Holliday proposed a four-way DNA junction as an intermediate in homologous recombination, and such Holliday junctions have since been identified as a central component in DNA recombination and repair. Phage T4 endonuclease VII (endo VII) was the first enzyme shown to resolve Holliday junctions into duplex DNAs by introducing symmetrical nicks in equivalent strands. Several Holliday junction resolvases have since been characterized, but an atomic structure of a resolvase complex with a Holliday junction remained elusive. Here we report the crystal structure of an inactive T4 endo VII(N62D) complexed with an immobile four-way junction with alternating arm lengths of 10 and 14 base pairs. The junction is a hybrid of the conventional square-planar and stacked-X conformation. Endo VII protrudes into the junction point from the minor groove side, opening it to a 14 A x 32 A parallelogram. This interaction interrupts the coaxial stacking, yet every base pair surrounding the junction remains intact. Additional interactions involve the positively charged protein and DNA phosphate backbones. Each scissile phosphate that is two base pairs from the crossover interacts with a Mg2+ ion in the active site. The similar overall shape and surface charge potential of the Holliday junction resolvases endo VII, RuvC, Ydc2, Hjc and RecU, despite having different folds, active site composition and DNA sequence preference, suggest a conserved binding mode for Holliday junctions. Crystal structure of T4 endonuclease VII resolving a Holliday junction.,Biertumpfel C, Yang W, Suck D Nature. 2007 Oct 4;449(7162):616-20. Epub 2007 Sep 16. PMID:17873859 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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