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1jn3

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(New page: 200px<br /><applet load="1jn3" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jn3, resolution 2.35&Aring;" /> '''FIDELITY PROPERTIES ...)
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[[Image:1jn3.jpg|left|200px]]<br /><applet load="1jn3" size="450" color="white" frame="true" align="right" spinBox="true"
 
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caption="1jn3, resolution 2.35&Aring;" />
 
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'''FIDELITY PROPERTIES AND STRUCTURE OF M282L MUTATOR MUTANT OF DNA POLYMERASE: SUBTLE STRUCTURAL CHANGES INFLUENCE THE MECHANISM OF NUCLEOTIDE DISCRIMINATION'''<br />
 
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==Overview==
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==FIDELITY PROPERTIES AND STRUCTURE OF M282L MUTATOR MUTANT OF DNA POLYMERASE: SUBTLE STRUCTURAL CHANGES INFLUENCE THE MECHANISM OF NUCLEOTIDE DISCRIMINATION==
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DNA polymerase beta (pol beta) offers a simple system to examine the role, of polymerase structure in the fidelity of DNA synthesis. In this study, the M282L variant of pol beta (M282Lbeta) was identified using an in vivo, genetic screen. Met282, which does not contact the DNA template or the, incoming deoxynucleoside triphosphate (dNTP) substrate, is located on, alpha-helix N of pol beta. This mutant enzyme demonstrates increased, mutagenesis in both in vivo and in vitro assays. M282Lbeta has a 7.5-fold, higher mutation frequency than wild-type pol beta; M282Lbeta commits a, variety of base substitution and frameshift errors. Transient-state, kinetic methods were used to investigate the mechanism of intrinsic, mutator activity of M282Lbeta. Results show an 11-fold decrease in dNTP, substrate discrimination at the level of ground-state binding. However, during the protein conformational change and/or phosphodiester bond, formation, the nucleotide discrimination is improved. X-ray, crystallography was utilized to gain insights into the structural basis of, the decreased DNA synthesis fidelity. Most of the structural changes are, localized to site 282 and the surrounding region in the C-terminal part of, the 31-kDa domain. Repositioning of mostly hydrophobic amino acid residues, in the core of the C-terminal portion generates a protein with enhanced, stability. The combination of structural and equilibrium unfolding data, suggests that the mechanism of nucleotide discrimination is possibly, affected by the compacting of the hydrophobic core around residue Leu282., Subsequent movement of an adjacent surface residue, Arg283, produces a, slight increase in volume of the pocket that may accommodate the incoming, correct base pair. The structural changes of M282Lbeta ultimately lead to, an overall reduction in polymerase fidelity.
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<StructureSection load='1jn3' size='340' side='right'caption='[[1jn3]], [[Resolution|resolution]] 2.35&Aring;' scene=''>
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== Structural highlights ==
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<table><tr><td colspan='2'>[[1jn3]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JN3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JN3 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]] 2.35&#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=1jn3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jn3 OCA], [https://pdbe.org/1jn3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jn3 RCSB], [https://www.ebi.ac.uk/pdbsum/1jn3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jn3 ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/DPOLB_RAT DPOLB_RAT] Repair polymerase that plays a key role in base-excision repair. Has 5'-deoxyribose-5-phosphate lyase (dRP lyase) activity that removes the 5' sugar phosphate and also acts as a DNA polymerase that adds one nucleotide to the 3' end of the arising single-nucleotide gap. Conducts 'gap-filling' DNA synthesis in a stepwise distributive fashion rather than in a processive fashion as for other DNA polymerases.
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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/jn/1jn3_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=1jn3 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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1JN3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Active as [http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1JN3 OCA].
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*[[DNA polymerase 3D structures|DNA polymerase 3D structures]]
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__TOC__
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==Reference==
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</StructureSection>
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A DNA polymerase beta mutator mutant with reduced nucleotide discrimination and increased protein stability., Shah AM, Conn DA, Li SX, Capaldi A, Jager J, Sweasy JB, Biochemistry. 2001 Sep 25;40(38):11372-81. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11560485 11560485]
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[[Category: Large Structures]]
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[[Category: DNA-directed DNA polymerase]]
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[[Category: Rattus norvegicus]]
[[Category: Rattus norvegicus]]
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[[Category: Single protein]]
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[[Category: Conn DA]]
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[[Category: Conn, D.A.]]
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[[Category: Jaeger J]]
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[[Category: Jaeger, J.]]
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[[Category: Sweasy JB]]
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[[Category: Sweasy, J.B.]]
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[[Category: dna polymerase beta (fragment)]]
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[[Category: mutant]]
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[[Category: nucleotide discrimination]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 18:23:48 2007''
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Current revision

FIDELITY PROPERTIES AND STRUCTURE OF M282L MUTATOR MUTANT OF DNA POLYMERASE: SUBTLE STRUCTURAL CHANGES INFLUENCE THE MECHANISM OF NUCLEOTIDE DISCRIMINATION

PDB ID 1jn3

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