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==Solution Structure of the theta subunit of DNA polymerase III from E. coli== | |||
<StructureSection load='2ae9' size='340' side='right'caption='[[2ae9]]' scene=''> | |||
| | == Structural highlights == | ||
<table><tr><td colspan='2'>[[2ae9]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AE9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2AE9 FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=2ae9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ae9 OCA], [https://pdbe.org/2ae9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2ae9 RCSB], [https://www.ebi.ac.uk/pdbsum/2ae9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2ae9 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/HOLE_ECOLI HOLE_ECOLI] DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. The exact function of the theta subunit is unknown. | |||
== 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/ae/2ae9_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=2ae9 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The catalytic core of Escherichia coli DNA polymerase III holoenzyme contains three subunits: alpha, epsilon, and theta. The alpha subunit contains the polymerase, and the epsilon subunit contains the exonucleolytic proofreading function. The small (8-kDa) theta subunit binds only to epsilon. Its function is not well understood, although it was shown to exert a small stabilizing effect on the epsilon proofreading function. In order to help elucidate its function, we undertook a determination of its solution structure. In aqueous solution, theta yielded poor-quality nuclear magnetic resonance spectra, presumably due to conformational exchange and/or protein aggregation. Based on our recently determined structure of the theta homolog from bacteriophage P1, named HOT, we constructed a homology model of theta. This model suggested that the unfavorable behavior of theta might arise from exposed hydrophobic residues, particularly toward the end of alpha-helix 3. In gel filtration studies, theta elutes later than expected, indicating that aggregation is potentially responsible for these problems. To address this issue, we recorded 1H-15N heteronuclear single quantum correlation (HSQC) spectra in water-alcohol mixed solvents and observed substantially improved dispersion and uniformity of peak intensities, facilitating a structural determination under these conditions. The structure of theta in 60/40 (vol/vol) water-methanol is similar to that of HOT but differs significantly from a previously reported theta structure. The new theta structure is expected to provide additional insight into its physiological role and its effect on the epsilon proofreading subunit. | |||
Nuclear magnetic resonance solution structure of the Escherichia coli DNA polymerase III theta subunit.,Mueller GA, Kirby TW, DeRose EF, Li D, Schaaper RM, London RE J Bacteriol. 2005 Oct;187(20):7081-9. PMID:16199579<ref>PMID:16199579</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 2ae9" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[DNA polymerase 3D structures|DNA polymerase 3D structures]] | |||
== References == | |||
== | <references/> | ||
__TOC__ | |||
</StructureSection> | |||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Derose | [[Category: Derose EF]] | ||
[[Category: Kirby | [[Category: Kirby TW]] | ||
[[Category: Li | [[Category: Li D]] | ||
[[Category: London | [[Category: London RE]] | ||
[[Category: Mueller | [[Category: Mueller GA]] | ||
[[Category: Schaaper | [[Category: Schaaper RM]] | ||
Latest revision as of 11:17, 15 May 2024
Solution Structure of the theta subunit of DNA polymerase III from E. coliSolution Structure of the theta subunit of DNA polymerase III from E. coli
Structural highlights
FunctionHOLE_ECOLI DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3' to 5' exonuclease activity. The exact function of the theta subunit is unknown. 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 PubMedThe catalytic core of Escherichia coli DNA polymerase III holoenzyme contains three subunits: alpha, epsilon, and theta. The alpha subunit contains the polymerase, and the epsilon subunit contains the exonucleolytic proofreading function. The small (8-kDa) theta subunit binds only to epsilon. Its function is not well understood, although it was shown to exert a small stabilizing effect on the epsilon proofreading function. In order to help elucidate its function, we undertook a determination of its solution structure. In aqueous solution, theta yielded poor-quality nuclear magnetic resonance spectra, presumably due to conformational exchange and/or protein aggregation. Based on our recently determined structure of the theta homolog from bacteriophage P1, named HOT, we constructed a homology model of theta. This model suggested that the unfavorable behavior of theta might arise from exposed hydrophobic residues, particularly toward the end of alpha-helix 3. In gel filtration studies, theta elutes later than expected, indicating that aggregation is potentially responsible for these problems. To address this issue, we recorded 1H-15N heteronuclear single quantum correlation (HSQC) spectra in water-alcohol mixed solvents and observed substantially improved dispersion and uniformity of peak intensities, facilitating a structural determination under these conditions. The structure of theta in 60/40 (vol/vol) water-methanol is similar to that of HOT but differs significantly from a previously reported theta structure. The new theta structure is expected to provide additional insight into its physiological role and its effect on the epsilon proofreading subunit. Nuclear magnetic resonance solution structure of the Escherichia coli DNA polymerase III theta subunit.,Mueller GA, Kirby TW, DeRose EF, Li D, Schaaper RM, London RE J Bacteriol. 2005 Oct;187(20):7081-9. PMID:16199579[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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