1mz8: Difference between revisions
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[[Image:1mz8.gif|left|200px]] | [[Image:1mz8.gif|left|200px]] | ||
'''CRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC ION''' | {{Structure | ||
|PDB= 1mz8 |SIZE=350|CAPTION= <scene name='initialview01'>1mz8</scene>, resolution 2.00Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene> and <scene name='pdbligand=PO4:PHOSPHATE ION'>PO4</scene> | |||
|ACTIVITY= | |||
|GENE= cei7 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]), cea7 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | |||
}} | |||
'''CRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC ION''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1MZ8 is a [ | 1MZ8 is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MZ8 OCA]. | ||
==Reference== | ==Reference== | ||
Metal ions and phosphate binding in the H-N-H motif: crystal structures of the nuclease domain of ColE7/Im7 in complex with a phosphate ion and different divalent metal ions., Sui MJ, Tsai LC, Hsia KC, Doudeva LG, Ku WY, Han GW, Yuan HS, Protein Sci. 2002 Dec;11(12):2947-57. PMID:[http:// | Metal ions and phosphate binding in the H-N-H motif: crystal structures of the nuclease domain of ColE7/Im7 in complex with a phosphate ion and different divalent metal ions., Sui MJ, Tsai LC, Hsia KC, Doudeva LG, Ku WY, Han GW, Yuan HS, Protein Sci. 2002 Dec;11(12):2947-57. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12441392 12441392] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
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[[Category: h-n-h motif]] | [[Category: h-n-h motif]] | ||
''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 12:50:00 2008'' | ||
Revision as of 13:50, 20 March 2008
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| , resolution 2.00Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Gene: | cei7 (Escherichia coli), cea7 (Escherichia coli) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC ION
OverviewOverview
H-N-H is a motif found in the nuclease domain of a subfamily of bacteria toxins, including colicin E7, that are capable of cleaving DNA nonspecifically. This H-N-H motif has also been identified in a subfamily of homing endonucleases, which cleave DNA site specifically. To better understand the role of metal ions in the H-N-H motif during DNA hydrolysis, we crystallized the nuclease domain of colicin E7 (nuclease-ColE7) in complex with its inhibitor Im7 in two different crystal forms, and we resolved the structures of EDTA-treated, Zn(2+)-bound and Mn(2+)-bound complexes in the presence of phosphate ions at resolutions of 2.6 A to 2.0 A. This study offers the first determination of the structure of a metal-free and substrate-free enzyme in the H-N-H family. The H-N-H motif contains two antiparallel beta-strands linked to a C-terminal alpha-helix, with a divalent metal ion located in the center. Here we show that the metal-binding sites in the center of the H-N-H motif, for the EDTA-treated and Mg(2+)-soaked complex crystals, were occupied by water molecules, indicating that an alkaline earth metal ion does not reside in the same position as a transition metal ion in the H-N-H motif. However, a Zn(2+) or Mn(2+) ions were observed in the center of the H-N-H motif in cases of Zn(2+) or Mn(2+)-soaked crystals, as confirmed in anomalous difference maps. A phosphate ion was found to bridge between the divalent transition metal ion and His545. Based on these structures and structural comparisons with other nucleases, we suggest a functional role for the divalent transition metal ion in the H-N-H motif in stabilizing the phosphoanion in the transition state during hydrolysis.
About this StructureAbout this Structure
1MZ8 is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Metal ions and phosphate binding in the H-N-H motif: crystal structures of the nuclease domain of ColE7/Im7 in complex with a phosphate ion and different divalent metal ions., Sui MJ, Tsai LC, Hsia KC, Doudeva LG, Ku WY, Han GW, Yuan HS, Protein Sci. 2002 Dec;11(12):2947-57. PMID:12441392
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