2OST

The structure of a bacterial homing endonuclease : I-Ssp6803I

Summary for 2OST

• Entry DOI: 10.2210/pdb2ost/pdb
• Descriptor: Synthetic DNA 29 MER, Putative endonuclease, CALCIUM ION, ... (5 entities in total)
• Functional Keywords: protein-dna complex, restriction enzyme fold, pd-(d/e)-xk motif, homing endonuclease, group i intron, hydrolase-dna complex, hydrolase/dna
• Biological source: Synechocystis sp.; More
• Total number of polymer chains: 6
• Total formula weight: 87532.39

Authors

Zhao, L.,Bonocora, R.P.,Shub, D.A.,Stoddard, B.L. (deposition date: 2007-02-06, release date: 2007-03-20, Last modification date: 2024-02-21)

Primary citation

Zhao, L.,Bonocora, R.P.,Shub, D.A.,Stoddard, B.L.
The restriction fold turns to the dark side: a bacterial homing endonuclease with a PD-(D/E)-XK motif.
Embo J., 26:2432-2442, 2007

PubMed Abstract: 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.

PubMed: 17410205
DOI: 10.1038/sj.emboj.7601672

Experimental method

X-RAY DIFFRACTION (3.1 Å)