View source for 2jaz


==CRYSTAL STRUCTURE OF THE MUTANT N560D OF THE NUCLEASE DOMAIN OF COLE7 IN COMPLEX WITH IM7==
<StructureSection load='2jaz' size='340' side='right'caption='[[2jaz]], [[Resolution|resolution]] 2.03&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2jaz]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Ecow3 Ecow3]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2JAZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2JAZ FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[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]], [[2jb0|2jb0]]</div></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2jaz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2jaz OCA], [https://pdbe.org/2jaz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2jaz RCSB], [https://www.ebi.ac.uk/pdbsum/2jaz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2jaz ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/IMM7_ECOLX IMM7_ECOLX]] This protein is able to protect a cell, which harbors the plasmid ColE7 encoding colicin E7, against colicin E7, it binds specifically to the DNase-type colicin and inhibits its bactericidal activity. Dimeric ImmE7 may possess a RNase activity that cleaves its own mRNA at a specific site and thus autoregulates translational expression of the downstream ceiE7 gene as well as degradation of the upstream ceaE7 mRNA. [[https://www.uniprot.org/uniprot/CEA7_ECOLX CEA7_ECOLX]] This plasmid-coded bactericidal protein is an endonuclease active on both single- and double-stranded DNA but with undefined specificity.  Colicins are polypeptide toxins produced by and active against E.coli and closely related bacteria. 
== 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/ja/2jaz_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/main_output.php?pdb_ID=2jaz ConSurf].
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== 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&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2jaz" style="background-color:#fffaf0;"></div>

==See Also==
*[[Colicin 3D structures|Colicin 3D structures]]
*[[Colicin immunity protein 3D structures|Colicin immunity protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Ecow3]]
[[Category: Large Structures]]
[[Category: Huang, H]]
[[Category: Yuan, H S]]
[[Category: Antibiotic]]
[[Category: Antimicrobial]]
[[Category: Bacteriocin]]
[[Category: Bacteriocin immunity]]
[[Category: Dna hydrolysis]]
[[Category: Endonuclease]]
[[Category: H-n-h motif]]
[[Category: His metal finger motif]]
[[Category: Hydrolase]]
[[Category: Hydrolase-inhibitor complex]]
[[Category: Hydrolase/inhibitor]]
[[Category: Metal-binding]]
[[Category: Nuclease]]
[[Category: Plasmid]]
[[Category: Toxin]]
[[Category: Zinc]]