1g9y: Difference between revisions
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[[Image:1g9y.gif|left|200px]] | [[Image:1g9y.gif|left|200px]] | ||
'''HOMING ENDONUCLEASE I-CREI / DNA SUBSTRATE COMPLEX WITH CALCIUM''' | {{Structure | ||
|PDB= 1g9y |SIZE=350|CAPTION= <scene name='initialview01'>1g9y</scene>, resolution 2.05Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=CA:CALCIUM ION'>CA</scene> | |||
|ACTIVITY= | |||
|GENE= CR.LSU INTRON OF CHOROPLAST 23S RRNA GENE ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3055 Chlamydomonas reinhardtii]) | |||
}} | |||
'''HOMING ENDONUCLEASE I-CREI / DNA SUBSTRATE COMPLEX WITH CALCIUM''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1G9Y is a [ | 1G9Y is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii Chlamydomonas reinhardtii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1G9Y OCA]. | ||
==Reference== | ==Reference== | ||
The homing endonuclease I-CreI uses three metals, one of which is shared between the two active sites., Chevalier BS, Monnat RJ Jr, Stoddard BL, Nat Struct Biol. 2001 Apr;8(4):312-6. PMID:[http:// | The homing endonuclease I-CreI uses three metals, one of which is shared between the two active sites., Chevalier BS, Monnat RJ Jr, Stoddard BL, Nat Struct Biol. 2001 Apr;8(4):312-6. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11276249 11276249] | ||
[[Category: Chlamydomonas reinhardtii]] | [[Category: Chlamydomonas reinhardtii]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: nuclease mechanism]] | [[Category: nuclease mechanism]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:20:21 2008'' | ||
Revision as of 12:20, 20 March 2008
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| , resolution 2.05Å | |||||||
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| Ligands: | |||||||
| Gene: | CR.LSU INTRON OF CHOROPLAST 23S RRNA GENE (Chlamydomonas reinhardtii) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
HOMING ENDONUCLEASE I-CREI / DNA SUBSTRATE COMPLEX WITH CALCIUM
OverviewOverview
Homing endonucleases, like restriction enzymes, cleave double-stranded DNA at specific target sites. The cleavage mechanism(s) utilized by LAGLIDADG endonucleases have been difficult to elucidate; their active sites are divergent, and only one low resolution cocrystal structure has been determined. Here we report two high resolution structures of the dimeric I-CreI homing endonuclease bound to DNA: a substrate complex with calcium and a product complex with magnesium. The bound metals in both complexes are verified by manganese anomalous difference maps. The active sites are positioned close together to facilitate cleavage across the DNA minor groove; each contains one metal ion bound between a conserved aspartate (Asp 20) and a single scissile phosphate. A third metal ion bridges the two active sites. This divalent cation is bound between aspartate residues from the active site of each subunit and is in simultaneous contact with the scissile phosphates of both DNA strands. A metal-bound water molecule acts as the nucleophile and is part of an extensive network of ordered water molecules that are positioned by enzyme side chains. These structures illustrate a unique variant of a two-metal endonuclease mechanism is employed by the highly divergent LAGLIDADG enzyme family.
About this StructureAbout this Structure
1G9Y is a Single protein structure of sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA.
ReferenceReference
The homing endonuclease I-CreI uses three metals, one of which is shared between the two active sites., Chevalier BS, Monnat RJ Jr, Stoddard BL, Nat Struct Biol. 2001 Apr;8(4):312-6. PMID:11276249
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