Structural highlights
Function
[PPO1_PHYPO] Mediates the homing of a group I intron in the ribosomal DNA. Makes a four-base staggered cut in its ribosomal DNA target sequence.
Publication Abstract from PubMed
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.
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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Galburt EA, Chevalier B, Tang W, Jurica MS, Flick KE, Monnat RJ Jr, Stoddard BL. A novel endonuclease mechanism directly visualized for I-PpoI. Nat Struct Biol. 1999 Dec;6(12):1096-9. PMID:10581547 doi:10.1038/70027
