View source for 2ae9

[[Image:2ae9.gif|left|200px]]<br /><applet load="2ae9" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="2ae9" />
'''Solution Structure of the theta subunit of DNA polymerase III from E. coli'''<br />

==Overview==
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.

==About this Structure==
2AE9 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/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=2AE9 OCA]. 

==Reference==
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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16199579 16199579]
[[Category: DNA-directed DNA polymerase]]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Derose, E.F.]]
[[Category: Kirby, T.W.]]
[[Category: Li, D.]]
[[Category: London, R.E.]]
[[Category: Mueller, G.A.]]
[[Category: Schaaper, R.M.]]
[[Category: 3 helices]]
[[Category: all helical]]

''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 08:04:28 2007''