6nju

Mouse endonuclease G mutant H97A bound to A-DNA

spinqualitylabelsall models 6nju, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6nju is a 5 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.35Å Ligands: CL, MG, TRS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NUCG_MOUSE Cleaves DNA at double-stranded (DG)n.(DC)n and at single-stranded (DC)n tracts. In addition to deoxyribonuclease activities, also has ribonuclease (RNase) and RNase H activities. Capable of generating the RNA primers required by DNA polymerase gamma to initiate replication of mitochondrial DNA (By similarity). Publication Abstract from PubMed Modified DNA bases functionally distinguish the taxonomic forms of life-5-methylcytosine separates prokaryotes from eukaryotes and 5-hydroxymethylcytosine (5hmC) invertebrates from vertebrates. We demonstrate here that mouse endonuclease G (mEndoG) shows specificity for both 5hmC and Holliday junctions. The enzyme has higher affinity (>50-fold) for junctions over duplex DNAs. A 5hmC-modification shifts the position of the cut site and increases the rate of DNA cleavage in modified versus unmodified junctions. The crystal structure of mEndoG shows that a cysteine (Cys69) is positioned to recognize 5hmC through a thiol-hydroxyl hydrogen bond. Although this Cys is conserved from worms to mammals, a two amino acid deletion in the vertebrate relative to the invertebrate sequence unwinds an alpha-helix, placing the thiol of Cys69 into the mEndoG active site. Mutations of Cys69 with alanine or serine show 5hmC-specificity that mirrors the hydrogen bonding potential of the side chain (C-H < S-H < O-H). A second orthogonal DNA binding site identified in the mEndoG structure accommodates a second arm of a junction. Thus, the specificity of mEndoG for 5hmC and junctions derives from structural adaptations that distinguish the vertebrate from the invertebrate enzyme, thereby thereby supporting a role for 5hmC in recombination processes. Structural adaptation of vertebrate endonuclease G for 5-hydroxymethylcytosine recognition and function.,Vander Zanden CM, Czarny RS, Ho EN, Robertson AB, Ho PS Nucleic Acids Res. 2020 Feb 25. pii: 5755888. doi: 10.1093/nar/gkaa117. PMID:32095813 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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