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| [[Image:2ae9.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_2ae9| PDB=2ae9 | SCENE= }} | | {{STRUCTURE_2ae9| PDB=2ae9 | SCENE= }} |
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| '''Solution Structure of the theta subunit of DNA polymerase III from E. coli'''
| | ===Solution Structure of the theta subunit of DNA polymerase III from E. coli=== |
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| ==Overview==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_16199579}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 16199579 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_16199579}} |
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| ==About this Structure== | | ==About this Structure== |
| 2AE9 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AE9 OCA]. | | 2AE9 is a [[Single protein]] structure of sequence from [http://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]. |
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| ==Reference== | | ==Reference== |
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| [[Category: 3 helice]] | | [[Category: 3 helice]] |
| [[Category: All helical]] | | [[Category: All helical]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 18:56:18 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 06:46:10 2008'' |
