1t9j | pdb_00001t9j

I-CreI(Q47E)/DNA complex

spinqualitylabelsall models 1t9j, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1t9j is a 4 chain structure with sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1g9y, 1g9z, 1t9i Gene: CR.LSU INTRON OF CHOROPLAST 23S RRNA GENE (Chlamydomonas reinhardtii) Resources: FirstGlance, OCA, RCSB, PDBsum Function [DNE1_CHLRE] Endonuclease involved in group I intron homing. Recognizes and cleaves a 19-24 bp palindromic DNA site. 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 The LAGLIDADG homing endonucleases include free-standing homodimers, pseudosymmetric monomers, and related enzyme domains embedded within inteins. DNA-bound structures of homodimeric I-CreI and monomeric I-SceI indicate that three catalytic divalent metal ions are distributed across a pair of overlapping active sites, with one shared metal participating in both strand cleavage reactions. These structures differ in the precise position and binding interactions of the metals. We have studied the metal dependence for the I-CreI homodimer using site-directed mutagenesis of active site residues and assays of binding affinity and cleavage activity. We have also reassessed the binding of a nonactivating metal ion (calcium) in the wild-type enzyme-substrate complex, and determined the DNA-bound structure of two inactive enzyme mutants. The conclusion of these studies is that the catalytic mechanism of symmetric LAGLIDADG homing endonucleases, and probably many of their monomeric cousins, involves a canonical two-metal mechanism in each of two active sites, which are chemically and structurally tethered to one another by a shared metal ion. Failure to occupy the shared metal site, as observed in the presence of calcium or when the metal-binding side chain from the LAGLIDADG motif (Asp 20) is mutated to asparagine, prevents cleavage by the enzyme. Metal-dependent DNA cleavage mechanism of the I-CreI LAGLIDADG homing endonuclease.,Chevalier B, Sussman D, Otis C, Noel AJ, Turmel M, Lemieux C, Stephens K, Monnat RJ Jr, Stoddard BL Biochemistry. 2004 Nov 9;43(44):14015-26. PMID:15518550 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease

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