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[[Image: | ==CRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC ION== | ||
<StructureSection load='1mz8' size='340' side='right' caption='[[1mz8]], [[Resolution|resolution]] 2.00Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1mz8]] is a 4 chain structure with sequence 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]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1MZ8 FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[7cei|7cei]]</td></tr> | |||
<tr><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">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])</td></tr> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mz8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mz8 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1mz8 RCSB], [http://www.ebi.ac.uk/pdbsum/1mz8 PDBsum]</span></td></tr> | |||
<table> | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/mz/1mz8_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
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. | |||
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<ref>PMID:12441392</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Colicin|Colicin]] | *[[Colicin|Colicin]] | ||
*[[Colicin Immunity Protein|Colicin Immunity Protein]] | *[[Colicin Immunity Protein|Colicin Immunity Protein]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
</StructureSection> | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Doudeva, L G.]] | [[Category: Doudeva, L G.]] | ||
Revision as of 18:23, 28 September 2014
CRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC IONCRYSTAL STRUCTURES OF THE NUCLEASE DOMAIN OF COLE7/IM7 IN COMPLEX WITH A PHOSPHATE ION AND A ZINC ION
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedH-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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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