| Literature DB >> 10581547 |
E A Galburt1, B Chevalier, W Tang, M S Jurica, K E Flick, R J Monnat, B L Stoddard.
Abstract
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.Entities:
Mesh：
Substances：
Year: 1999 PMID： 10581547 DOI： 10.1038/70027
Source DB: PubMed Journal: Nat Struct Biol ISSN： 1072-8368