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| | <StructureSection load='1mz8' size='340' side='right'caption='[[1mz8]], [[Resolution|resolution]] 2.00Å' scene=''> | | <StructureSection load='1mz8' size='340' side='right'caption='[[1mz8]], [[Resolution|resolution]] 2.00Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1mz8]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. 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://proteopedia.org/fgij/fg.htm?mol=1MZ8 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1mz8]] is a 4 chain structure with sequence from [https://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 [https://proteopedia.org/fgij/fg.htm?mol=1MZ8 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> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[7cei|7cei]]</div></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='gene'><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 "Bacillus coli" Migula 1895]), cea7 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 "Bacillus coli" Migula 1895])</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=1mz8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mz8 OCA], [https://pdbe.org/1mz8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mz8 RCSB], [https://www.ebi.ac.uk/pdbsum/1mz8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mz8 ProSAT]</span></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1mz8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mz8 OCA], [http://pdbe.org/1mz8 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1mz8 RCSB], [http://www.ebi.ac.uk/pdbsum/1mz8 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1mz8 ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://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. [[http://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. | + | [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. |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Bacillus coli migula 1895]] | + | [[Category: Escherichia coli]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Doudeva, L G]] | + | [[Category: Doudeva LG]] |
| - | [[Category: Han, G W]] | + | [[Category: Han GW]] |
| - | [[Category: Hsia, K C]] | + | [[Category: Hsia KC]] |
| - | [[Category: Ku, W Y]] | + | [[Category: Ku WY]] |
| - | [[Category: Sui, M J]] | + | [[Category: Sui MJ]] |
| - | [[Category: Tsai, L C]] | + | [[Category: Tsai LC]] |
| - | [[Category: Yuan, H S]] | + | [[Category: Yuan HS]] |
| - | [[Category: H-n-h motif]]
| + | |
| - | [[Category: Hydrolase-protein binding complex]]
| + | |
| - | [[Category: Toxin]]
| + | |
| Structural highlights
Function
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.
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 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[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Sui MJ, Tsai LC, Hsia KC, Doudeva LG, Ku WY, Han GW, Yuan HS. 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. Protein Sci. 2002 Dec;11(12):2947-57. PMID:12441392
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