2fkh

Crystal Form II of Pre-Reactive Complex of Restriction Endonuclease HinP1I with Cognate DNA and Calcium Ions

spinqualitylabelsall models 2fkh, resolution 3.09Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2fkh is a 3 chain structure with sequence from Haemophilus influenzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.09Å Ligands: CA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5I6E6_HAEIF Publication Abstract from PubMed HinP1I recognizes and cleaves the palindromic tetranucleotide sequence G downward arrowCGC in DNA. We report three structures of HinP1I-DNA complexes: in the presence of Ca(2+) (pre-reactive complex), in the absence of metal ion (binary complex) and in the presence of Mg(2+) (post-reactive complex). HinP1I forms a back-to-back dimer with two active sites and two DNA duplexes bound on the outer surfaces of the dimer facing away from each other. The 10 bp DNA duplexes undergo protein-induced distortions exhibiting features of A-, B- and Z-conformations: bending on one side (by intercalation of a phenylalanine side chain into the major groove), base flipping on the other side of the recognition site (by expanding the step rise distance of the local base pair to Z-form) and a local A-form conformation between the two central C:G base pairs of the recognition site (by binding of the N-terminal helix in the minor groove). In the pre- and post-reactive complexes, two metals (Ca(2+) or Mg(2+)) are found in the active site. The enzyme appears to cleave DNA sequentially, hydrolyzing first one DNA strand, as seen in the post-reactive complex in the crystalline state, and then the other, as supported by the observation that, in solution, a nicked DNA intermediate accumulates before linearization. DNA nicking by HinP1I endonuclease: bending, base flipping and minor groove expansion.,Horton JR, Zhang X, Maunus R, Yang Z, Wilson GG, Roberts RJ, Cheng X Nucleic Acids Res. 2006 Feb 9;34(3):939-48. Print 2006. PMID:16473850 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Endonuclease 3D structures

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