2fl3
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(New page: 200px<br /><applet load="2fl3" size="350" color="white" frame="true" align="right" spinBox="true" caption="2fl3, resolution 2.39Å" /> '''Binary Complex of Re...)
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Revision as of 17:39, 29 January 2008
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Binary Complex of Restriction Endonuclease HinP1I with Cognate DNA
Overview
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.
About this Structure
2FL3 is a Single protein structure of sequence from Haemophilus influenzae. Active as Type II site-specific deoxyribonuclease, with EC number 3.1.21.4 Full crystallographic information is available from OCA.
Reference
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
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