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[[Image: | ==CRYSTAL STRUCTURE OF THE MUTANT H573A OF THE NUCLEASE DOMAIN OF COLE7 IN COMPLEX WITH IM7== | ||
<StructureSection load='2jb0' size='340' side='right' caption='[[2jb0]], [[Resolution|resolution]] 1.91Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2jb0]] is a 2 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=2JB0 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2JB0 FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ZN:ZINC+ION'>ZN</scene><br> | |||
<tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1ayi|1ayi]], [[1cei|1cei]], [[1mz8|1mz8]], [[1ujz|1ujz]], [[1unk|1unk]], [[1znv|1znv]], [[2erh|2erh]], [[7cei|7cei]], [[1m08|1m08]], [[1pt3|1pt3]], [[1zns|1zns]], [[2axc|2axc]], [[2ivh|2ivh]], [[2jaz|2jaz]]</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=2jb0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2jb0 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=2jb0 RCSB], [http://www.ebi.ac.uk/pdbsum/2jb0 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/jb/2jb0_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 == | |||
The HNH motif is a small nucleic acid binding and cleavage module, widespread in metal finger endonucleases in all life kingdoms. Here we studied a non-specific endonuclease, the nuclease domain of ColE7 (N-ColE7), to decipher the role of the conserved asparagine and histidine residues in the HNH motif. We found, using fluorescence resonance energy transfer (FRET) assays, that the DNA hydrolysis activity of H545 N-ColE7 mutants was completely abolished while activities of N560 and H573 mutants varied from 6.9% to 83.2% of the wild-type activity. The crystal structures of three N-ColE7 mutants in complex with the inhibitor Im7, N560A-Im7, N560D-Im7 and H573A-Im7, were determined at a resolution of 1.9 A to 2.2 A. H573 is responsible for metal ion binding in the wild-type protein, as the zinc ion is still partially associated in the structure of H573A, suggesting that H573 plays a supportive role in metal binding. Both N560A and N560D contain a disordered loop in the HNH motif due to the disruption of the hydrogen bond network surrounding the side-chain of residue 560, and as a result, the imidazole ring of the general base residue H545 is tilted slightly and the scissile phosphate is shifted, leading to the large reductions in hydrolysis activities. These results suggest that the highly conserved asparagine in the HNH motif, in general, plays a structural role in constraining the loop in the metal finger structure and keeping the general base histidine and scissile phosphate in the correct position for DNA hydrolysis. | |||
The conserved asparagine in the HNH motif serves an important structural role in metal finger endonucleases.,Huang H, Yuan HS J Mol Biol. 2007 May 4;368(3):812-21. Epub 2007 Feb 27. PMID:17368670<ref>PMID:17368670</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: Huang, H.]] | [[Category: Huang, H.]] | ||
Revision as of 06:36, 29 September 2014
CRYSTAL STRUCTURE OF THE MUTANT H573A OF THE NUCLEASE DOMAIN OF COLE7 IN COMPLEX WITH IM7CRYSTAL STRUCTURE OF THE MUTANT H573A OF THE NUCLEASE DOMAIN OF COLE7 IN COMPLEX WITH IM7
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 PubMedThe HNH motif is a small nucleic acid binding and cleavage module, widespread in metal finger endonucleases in all life kingdoms. Here we studied a non-specific endonuclease, the nuclease domain of ColE7 (N-ColE7), to decipher the role of the conserved asparagine and histidine residues in the HNH motif. We found, using fluorescence resonance energy transfer (FRET) assays, that the DNA hydrolysis activity of H545 N-ColE7 mutants was completely abolished while activities of N560 and H573 mutants varied from 6.9% to 83.2% of the wild-type activity. The crystal structures of three N-ColE7 mutants in complex with the inhibitor Im7, N560A-Im7, N560D-Im7 and H573A-Im7, were determined at a resolution of 1.9 A to 2.2 A. H573 is responsible for metal ion binding in the wild-type protein, as the zinc ion is still partially associated in the structure of H573A, suggesting that H573 plays a supportive role in metal binding. Both N560A and N560D contain a disordered loop in the HNH motif due to the disruption of the hydrogen bond network surrounding the side-chain of residue 560, and as a result, the imidazole ring of the general base residue H545 is tilted slightly and the scissile phosphate is shifted, leading to the large reductions in hydrolysis activities. These results suggest that the highly conserved asparagine in the HNH motif, in general, plays a structural role in constraining the loop in the metal finger structure and keeping the general base histidine and scissile phosphate in the correct position for DNA hydrolysis. The conserved asparagine in the HNH motif serves an important structural role in metal finger endonucleases.,Huang H, Yuan HS J Mol Biol. 2007 May 4;368(3):812-21. Epub 2007 Feb 27. PMID:17368670[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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