1cz0
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(New page: 200px<br /><applet load="1cz0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cz0, resolution 2.1Å" /> '''INTRON ENCODED HOMING...)
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Revision as of 10:44, 20 November 2007
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INTRON ENCODED HOMING ENDONUCLEASE I-PPOI/DNA COMPLEX LACKING CATALYTIC METAL ION
Overview
A novel mechanism of DNA endonucleolytic cleavage has been visualized for, the homing endonuclease I-PpoI by trapping the uncleaved enzyme-substrate, complex and comparing it to the previously visualized product complex., This enzyme employs a unique single metal mechanism. A magnesium ion is, coordinated by an asparagine residue and two DNA oxygen atoms and, stabilizes the phosphoanion transition state and the 3'oxygen leaving, group. A hydrolytic water molecule is activated by a histidine residue for, an in-line attack on the scissile phosphate. A strained, enzyme-substrate-metal complex is formed before cleavage, then relaxed, during the reaction.
About this Structure
1CZ0 is a Single protein structure of sequence from Physarum polycephalum with ZN and NA as ligands. Full crystallographic information is available from OCA.
Reference
A novel endonuclease mechanism directly visualized for I-PpoI., Galburt EA, Chevalier B, Tang W, Jurica MS, Flick KE, Monnat RJ Jr, Stoddard BL, Nat Struct Biol. 1999 Dec;6(12):1096-9. PMID:10581547
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