1kea: Difference between revisions
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New page: left|200px<br /><applet load="1kea" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kea, resolution 2.00Å" /> '''STRUCTURE OF A THERM... |
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[[Image:1kea.jpg|left|200px]]<br /><applet load="1kea" size=" | [[Image:1kea.jpg|left|200px]]<br /><applet load="1kea" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1kea, resolution 2.00Å" /> | caption="1kea, resolution 2.00Å" /> | ||
'''STRUCTURE OF A THERMOSTABLE THYMINE-DNA GLYCOSYLASE'''<br /> | '''STRUCTURE OF A THERMOSTABLE THYMINE-DNA GLYCOSYLASE'''<br /> | ||
==Overview== | ==Overview== | ||
The repair of T:G mismatches in DNA is key for maintaining bacterial | The repair of T:G mismatches in DNA is key for maintaining bacterial restriction/modification systems and gene silencing in higher eukaryotes. T:G mismatch repair can be initiated by a specific mismatch glycosylase (MIG) that is homologous to the helix-hairpin-helix (HhH) DNA repair enzymes. Here, we present a 2.0 A resolution crystal structure and complementary mutagenesis results for this thermophilic HhH MIG enzyme. The results suggest that MIG distorts the target thymine nucleotide by twisting the thymine base approximately 90 degrees away from its normal anti position within DNA. We propose that functionally significant differences exist in DNA repair enzyme extrahelical nucleotide binding and catalysis that are characteristic of whether the target base is damaged or is a normal base within a mispair. These results explain why pure HhH DNA glycosylases and combined glycosylase/AP lyases cannot be interconverted by simply altering their functional group chemistry, and how broad-specificity DNA glycosylase enzymes may weaken the glycosylic linkage to allow a variety of damaged DNA bases to be excised. | ||
==About this Structure== | ==About this Structure== | ||
1KEA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanothermobacter_thermautotrophicus Methanothermobacter thermautotrophicus] with ZN, ACT, CL and SF4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1KEA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanothermobacter_thermautotrophicus Methanothermobacter thermautotrophicus] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=ACT:'>ACT</scene>, <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=SF4:'>SF4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KEA OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Methanothermobacter thermautotrophicus]] | [[Category: Methanothermobacter thermautotrophicus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Arvai, A | [[Category: Arvai, A S.]] | ||
[[Category: Begley, T | [[Category: Begley, T J.]] | ||
[[Category: Cunningham, R | [[Category: Cunningham, R P.]] | ||
[[Category: Mol, C | [[Category: Mol, C D.]] | ||
[[Category: Tainer, J | [[Category: Tainer, J A.]] | ||
[[Category: ACT]] | [[Category: ACT]] | ||
[[Category: CL]] | [[Category: CL]] | ||
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[[Category: methylation]] | [[Category: methylation]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:33:11 2008'' | ||
