2ost
From Proteopedia
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The structure of a bacterial homing endonuclease : I-Ssp6803I
Overview
The homing endonuclease I-Ssp6803I causes the insertion of a group I intron into a bacterial tRNA gene-the only example of an invasive mobile intron within a bacterial genome. Using a computational fold prediction, mutagenic screen and crystal structure determination, we demonstrate that this protein is a tetrameric PD-(D/E)-XK endonuclease - a fold normally used to protect a bacterial genome from invading DNA through the action of restriction endonucleases. I-Ssp6803I uses its tetrameric assembly to promote recognition of a single long target site, whereas restriction endonuclease tetramers facilitate cooperative binding and cleavage of two short sites. The limited use of the PD-(D/E)-XK nucleases by mobile introns stands in contrast to their frequent use of LAGLIDADG and HNH endonucleases - which in turn, are rarely incorporated into restriction/modification systems.
About this Structure
2OST is a Single protein structure of sequence from Synechocystis sp.. Full crystallographic information is available from OCA.
Reference
The restriction fold turns to the dark side: a bacterial homing endonuclease with a PD-(D/E)-XK motif., Zhao L, Bonocora RP, Shub DA, Stoddard BL, EMBO J. 2007 May 2;26(9):2432-42. Epub 2007 Apr 5. PMID:17410205
Page seeded by OCA on Thu Mar 20 18:03:59 2008
