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1a73
From Proteopedia
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[[Image:1a73.gif|left|200px]] | [[Image:1a73.gif|left|200px]] | ||
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'''INTRON-ENCODED ENDONUCLEASE I-PPOI COMPLEXED WITH DNA''' | '''INTRON-ENCODED ENDONUCLEASE I-PPOI COMPLEXED WITH DNA''' | ||
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[[Category: Junior, R J.Monnat.]] | [[Category: Junior, R J.Monnat.]] | ||
[[Category: Stoddard, B L.]] | [[Category: Stoddard, B L.]] | ||
| - | [[Category: | + | [[Category: Dna binding]] |
| - | + | [[Category: Intron]] | |
| - | [[Category: | + | [[Category: Protein folding]] |
| - | [[Category: | + | [[Category: Zinc]] |
| - | [[Category: | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 09:54:47 2008'' |
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Revision as of 06:54, 2 May 2008
INTRON-ENCODED ENDONUCLEASE I-PPOI COMPLEXED WITH DNA
Overview
Homing endonucleases are a diverse collection of proteins that are encoded by genes with mobile, self-splicing introns. They have also been identified in self-splicing inteins (protein introns). These enzymes promote the movement of the DNA sequences that encode them from one chromosome location to another; they do this by making a site-specific double-strand break at a target site in an allele that lacks the corresponding mobile intron. The target sites recognized by these small endonucleases are generally long (14-44 base pairs). Four families of homing endonucleases have been identified, including the LAGLIDADG, the His-Cys box, the GIY-YIG and the H-N-H endonucleases. The first identified His-Cys box homing endonuclease was I-PpoI from the slime mould Physarum polycephalum. Its gene resides in one of only a few nuclear introns known to exhibit genetic mobility. Here we report the structure of the I-PpoI homing endonuclease bound to homing-site DNA determined to 1.8 A resolution. I-PpoI displays an elongated fold of dimensions 25 x 35 x 80 A, with mixed alpha/beta topology. Each I-PpoI monomer contains three antiparallel beta-sheets flanked by two long alpha-helices and a long carboxy-terminal tail, and is stabilized by two bound zinc ions 15 A apart. The enzyme possesses a new zinc-bound fold and endonuclease active site. The structure has been determined in both uncleaved substrate and cleaved product complexes.
About this Structure
1A73 is a Single protein structure of sequence from Physarum polycephalum. Full crystallographic information is available from OCA.
Reference
DNA binding and cleavage by the nuclear intron-encoded homing endonuclease I-PpoI., Flick KE, Jurica MS, Monnat RJ Jr, Stoddard BL, Nature. 1998 Jul 2;394(6688):96-101. PMID:9665136 Page seeded by OCA on Fri May 2 09:54:47 2008
