This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1cyq
From Proteopedia
| |||||||
| , resolution 1.93Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
INTRON ENCODED HOMING ENDONUCLEASE I-PPOI (H98A)/DNA HOMING SITE COMPLEX
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
1CYQ 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 Thu Mar 20 10:30:30 2008
