2sns

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[[Image:2sns.jpg|left|200px]]
 
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{{Structure
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==STAPHYLOCOCCAL NUCLEASE. PROPOSED MECHANISM OF ACTION BASED ON STRUCTURE OF ENZYME-THYMIDINE 3(PRIME),5(PRIME)-BIPHOSPHATE-CALCIUM ION COMPLEX AT 1.5-ANGSTROMS RESOLUTION==
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|PDB= 2sns |SIZE=350|CAPTION= <scene name='initialview01'>2sns</scene>, resolution 1.5&Aring;
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<StructureSection load='2sns' size='340' side='right'caption='[[2sns]], [[Resolution|resolution]] 1.50&Aring;' scene=''>
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|SITE=
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== Structural highlights ==
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|LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene> and <scene name='pdbligand=THP:THYMIDINE-3&#39;,5&#39;-DIPHOSPHATE'>THP</scene>
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<table><tr><td colspan='2'>[[2sns]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2SNS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2SNS FirstGlance]. <br>
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|ACTIVITY= [http://en.wikipedia.org/wiki/Hydrolase Hydrolase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.33.1 3.1.33.1]
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.5&#8491;</td></tr>
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|GENE=
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=THP:THYMIDINE-3,5-DIPHOSPHATE'>THP</scene></td></tr>
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}}
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2sns FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2sns OCA], [https://pdbe.org/2sns PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2sns RCSB], [https://www.ebi.ac.uk/pdbsum/2sns PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2sns ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/NUC_STAAU NUC_STAAU] Enzyme that catalyzes the hydrolysis of both DNA and RNA at the 5' position of the phosphodiester bond.
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== Evolutionary Conservation ==
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[[Image:Consurf_key_small.gif|200px|right]]
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Check<jmol>
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<jmolCheckbox>
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<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/sn/2sns_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
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<text>to colour the structure by Evolutionary Conservation</text>
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</jmolCheckbox>
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</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=2sns ConSurf].
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<div style="clear:both"></div>
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<div style="background-color:#fffaf0;">
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== Publication Abstract from PubMed ==
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The structure of the staphylococcal nuclease (EC 3.1.4.7)-thymidine 3',5'-bisphosphate-Ca(2+) (enzyme-inhibitor) complex has been extended to 1.5-A resolution by using much additional data and a phase refinement scheme based on an electron-density map modification procedure. By correlating this structure with the known properties of the enzyme, a mechanism of action is proposed that involves nucleophilic attack on phosphorus by a water molecule, which is bound to Glu-43, in line with the 5'-CH(2)O(H) leaving group. The carboxylate of Glu-43 promotes this attack by acting as a general base for the abstraction of a proton from the attacking water molecule. Nucleophilic attack is further facilitated by polarization of the phosphodiester by an ionic interaction between a Ca(2+) ion and a phosphate oxygen atom and by four hydrogen bonds to phosphate oxygen atoms from guanidinium ions of Arg-35 and Arg-87. These interactions may also catalyze the reaction by lowering the energy of a trigonal bipyramidal transition state. The hydrolysis of nucleic acid substrate proceeds by cleavage of the 5'-P-O bond to yield a free 5'-hydroxyl group and a terminal, 3'-phosphate monoester group. In the inhibitor complex the only general acid group found in a position to donate a proton to the leaving 5'-oxygen is the guanidinium ion of Arg-87. Alternative proton donors, presently lacking direct structural support, could be the phenolic hydroxyl group of Tyr-113 or a water molecule. The precision and rigidity of the location of the reactants at the active site and the probable dual binding and catalytic roles of the guanidinium ions of Arg-35 and Arg-87 are especially noteworthy.
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'''STAPHYLOCOCCAL NUCLEASE. PROPOSED MECHANISM OF ACTION BASED ON STRUCTURE OF ENZYME-THYMIDINE 3(PRIME),5(PRIME)-BIPHOSPHATE-CALCIUM ION COMPLEX AT 1.5-ANGSTROMS RESOLUTION'''
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Staphylococcal nuclease: proposed mechanism of action based on structure of enzyme-thymidine 3',5'-bisphosphate-calcium ion complex at 1.5-A resolution.,Cotton FA, Hazen EE Jr, Legg MJ Proc Natl Acad Sci U S A. 1979 Jun;76(6):2551-5. PMID:000288045<ref>PMID:000288045</ref>
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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</div>
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<div class="pdbe-citations 2sns" style="background-color:#fffaf0;"></div>
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==Overview==
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==See Also==
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The structure of the staphylococcal nuclease (EC 3.1.4.7)-thymidine 3',5'-bisphosphate-Ca(2+) (enzyme-inhibitor) complex has been extended to 1.5-A resolution by using much additional data and a phase refinement scheme based on an electron-density map modification procedure. By correlating this structure with the known properties of the enzyme, a mechanism of action is proposed that involves nucleophilic attack on phosphorus by a water molecule, which is bound to Glu-43, in line with the 5'-CH(2)O(H) leaving group. The carboxylate of Glu-43 promotes this attack by acting as a general base for the abstraction of a proton from the attacking water molecule. Nucleophilic attack is further facilitated by polarization of the phosphodiester by an ionic interaction between a Ca(2+) ion and a phosphate oxygen atom and by four hydrogen bonds to phosphate oxygen atoms from guanidinium ions of Arg-35 and Arg-87. These interactions may also catalyze the reaction by lowering the energy of a trigonal bipyramidal transition state. The hydrolysis of nucleic acid substrate proceeds by cleavage of the 5'-P-O bond to yield a free 5'-hydroxyl group and a terminal, 3'-phosphate monoester group. In the inhibitor complex the only general acid group found in a position to donate a proton to the leaving 5'-oxygen is the guanidinium ion of Arg-87. Alternative proton donors, presently lacking direct structural support, could be the phenolic hydroxyl group of Tyr-113 or a water molecule. The precision and rigidity of the location of the reactants at the active site and the probable dual binding and catalytic roles of the guanidinium ions of Arg-35 and Arg-87 are especially noteworthy.
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*[[Staphylococcal nuclease 3D structures|Staphylococcal nuclease 3D structures]]
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== References ==
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==About this Structure==
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<references/>
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2SNS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus]. This structure supersedes the now removed PDB entry 1SNS. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2SNS OCA].
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__TOC__
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</StructureSection>
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==Reference==
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[[Category: Large Structures]]
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Staphylococcal nuclease: proposed mechanism of action based on structure of enzyme-thymidine 3',5'-bisphosphate-calcium ion complex at 1.5-A resolution., Cotton FA, Hazen EE Jr, Legg MJ, Proc Natl Acad Sci U S A. 1979 Jun;76(6):2551-5. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/288045 288045]
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[[Category: Hydrolase]]
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[[Category: Single protein]]
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[[Category: Staphylococcus aureus]]
[[Category: Staphylococcus aureus]]
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[[Category: Cotton, F A.]]
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[[Category: Cotton FA]]
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[[Category: Hazenjunior, E E.]]
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[[Category: Hazen Jr EE]]
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[[Category: Legg, M J.]]
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[[Category: Legg MJ]]
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[[Category: CA]]
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[[Category: THP]]
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[[Category: hydrolase (phosphoric diester)]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 23 15:50:34 2008''
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Current revision

STAPHYLOCOCCAL NUCLEASE. PROPOSED MECHANISM OF ACTION BASED ON STRUCTURE OF ENZYME-THYMIDINE 3(PRIME),5(PRIME)-BIPHOSPHATE-CALCIUM ION COMPLEX AT 1.5-ANGSTROMS RESOLUTION

PDB ID 2sns

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