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1ako

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[[Image:1ako.gif|left|200px]]<br />
 
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<applet load="1ako" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1ako, resolution 1.7&Aring;" />
 
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'''EXONUCLEASE III FROM ESCHERICHIA COLI'''<br />
 
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==Overview==
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==EXONUCLEASE III FROM ESCHERICHIA COLI==
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The repair of DNA requires the removal of abasic sites, which are, constantly generated in vivo both spontaneously and by enzymatic removal, of uracil, and of bases damaged by active oxygen species, alkylating, agents and ionizing radiation. The major apurinic/apyrimidinic (AP), DNA-repair endonuclease in Escherichia coli is the multifunctional enzyme, exonuclease III, which also exhibits 3'-repair diesterase, 3'--&gt;5', exonuclease, 3'-phosphomonoesterase and ribonuclease activities. We report, here the 1.7 A resolution crystal structure of exonuclease III which, reveals a 2-fold symmetric, four-layered alpha beta fold with similarities, to both deoxyribonuclease I and RNase H. In the ternary complex determined, at 2.6 A resolution, Mn2+ and dCMP bind to exonuclease III at one end of, the alpha beta-sandwich, in a region dominated by positive electrostatic, potential. Residues conserved among AP endonucleases from bacteria to man, cluster within this active site and appear to participate in, phosphate-bond cleavage at AP sites through a nucleophilic attack, facilitated by a single bound metal ion.
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<StructureSection load='1ako' size='340' side='right'caption='[[1ako]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1ako]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AKO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AKO FirstGlance]. <br>
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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]] 1.7&#8491;</td></tr>
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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=1ako FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ako OCA], [https://pdbe.org/1ako PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ako RCSB], [https://www.ebi.ac.uk/pdbsum/1ako PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ako ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/EX3_ECOLI EX3_ECOLI] Major apurinic-apyrimidinic endonuclease of E.coli. It removes the damaged DNA at cytosines and guanines by cleaving on the 3'-side of the AP site by a beta-elimination reaction. It exhibits 3'-5'-exonuclease, 3'-phosphomonoesterase, 3'-repair diesterase and ribonuclease H activities.
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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/ak/1ako_consurf.spt"</scriptWhenChecked>
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<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=1ako ConSurf].
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<div style="clear:both"></div>
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==About this Structure==
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==See Also==
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1AKO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Exodeoxyribonuclease_III Exodeoxyribonuclease III], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.11.2 3.1.11.2] Structure known Active Site: MG1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1AKO OCA].
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*[[Endonuclease 3D structures|Endonuclease 3D structures]]
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*[[Exonuclease 3D structures|Exonuclease 3D structures]]
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==Reference==
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__TOC__
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Structure and function of the multifunctional DNA-repair enzyme exonuclease III., Mol CD, Kuo CF, Thayer MM, Cunningham RP, Tainer JA, Nature. 1995 Mar 23;374(6520):381-6. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=7885481 7885481]
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</StructureSection>
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[[Category: Escherichia coli]]
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[[Category: Escherichia coli K-12]]
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[[Category: Exodeoxyribonuclease III]]
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[[Category: Large Structures]]
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[[Category: Single protein]]
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[[Category: Cunningham RP]]
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[[Category: Cunningham, R.P.]]
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[[Category: Kuo C-F]]
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[[Category: Kuo, C.F.]]
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[[Category: Mol CD]]
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[[Category: Mol, C.D.]]
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[[Category: Tainer JA]]
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[[Category: Tainer, J.A.]]
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[[Category: Thayer MM]]
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[[Category: Thayer, M.M.]]
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[[Category: ap-endonuclease]]
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[[Category: dna repair]]
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[[Category: exonuclease]]
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[[Category: nuclease]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:04:00 2007''
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Current revision

EXONUCLEASE III FROM ESCHERICHIA COLI

PDB ID 1ako

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