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1cz0
From Proteopedia
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. 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 Page seeded by OCA on Fri May 2 13:15:23 2008
