1zyq
From Proteopedia
(New page: 200px<br /><applet load="1zyq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zyq, resolution 2.70Å" /> '''T7 DNA polymerase in...) |
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| - | [[Image:1zyq.gif|left|200px]]<br /><applet load="1zyq" size=" | + | [[Image:1zyq.gif|left|200px]]<br /><applet load="1zyq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1zyq, resolution 2.70Å" /> | caption="1zyq, resolution 2.70Å" /> | ||
'''T7 DNA polymerase in complex with 8oG and incoming ddATP'''<br /> | '''T7 DNA polymerase in complex with 8oG and incoming ddATP'''<br /> | ||
==Overview== | ==Overview== | ||
| - | 8-oxo-7,8-dihydroguanosine (8oG) is a highly mutagenic DNA lesion that | + | 8-oxo-7,8-dihydroguanosine (8oG) is a highly mutagenic DNA lesion that stably pairs with adenosine, forming 8oG(syn).dA(anti) Hoogsteen base pairs. DNA polymerases show different propensities to insert dCMP or dAMP opposite 8oG, but the molecular mechanisms that determine faithful or mutagenic bypass are poorly understood. Here, we report kinetic and structural data providing evidence that, in T7 DNA polymerase, residue Lys536 is responsible for attenuating the miscoding potential of 8oG. The Lys536Ala polymerase shows a significant increase in mutagenic 8oG bypass versus wild-type polymerase, and a crystal structure of the Lys536Ala mutant reveals a closed complex with an 8oG(syn).dATP mismatch in the polymerase active site, in contrast to the unproductive, open complex previously obtained by using wild-type polymerase. We propose that Lys536 acts as a steric and/or electrostatic filter that attenuates the miscoding potential of 8oG by normally interfering with the binding of 8oG in a syn conformation that pairs with dATP. |
==About this Structure== | ==About this Structure== | ||
| - | 1ZYQ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bacteriophage_t7 Bacteriophage t7] and [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MG and DAD as [http://en.wikipedia.org/wiki/ligands ligands]. 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:// | + | 1ZYQ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bacteriophage_t7 Bacteriophage t7] and [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=DAD:'>DAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. 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://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZYQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Bebenek, K.]] | [[Category: Bebenek, K.]] | ||
| - | [[Category: Brieba, L | + | [[Category: Brieba, L G.]] |
[[Category: Ellenberger, T.]] | [[Category: Ellenberger, T.]] | ||
| - | [[Category: Kokoska, R | + | [[Category: Kokoska, R J.]] |
| - | [[Category: Kunkel, T | + | [[Category: Kunkel, T A.]] |
[[Category: DAD]] | [[Category: DAD]] | ||
[[Category: MG]] | [[Category: MG]] | ||
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[[Category: fidelity]] | [[Category: fidelity]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:20:22 2008'' |
Revision as of 14:20, 21 February 2008
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T7 DNA polymerase in complex with 8oG and incoming ddATP
Overview
8-oxo-7,8-dihydroguanosine (8oG) is a highly mutagenic DNA lesion that stably pairs with adenosine, forming 8oG(syn).dA(anti) Hoogsteen base pairs. DNA polymerases show different propensities to insert dCMP or dAMP opposite 8oG, but the molecular mechanisms that determine faithful or mutagenic bypass are poorly understood. Here, we report kinetic and structural data providing evidence that, in T7 DNA polymerase, residue Lys536 is responsible for attenuating the miscoding potential of 8oG. The Lys536Ala polymerase shows a significant increase in mutagenic 8oG bypass versus wild-type polymerase, and a crystal structure of the Lys536Ala mutant reveals a closed complex with an 8oG(syn).dATP mismatch in the polymerase active site, in contrast to the unproductive, open complex previously obtained by using wild-type polymerase. We propose that Lys536 acts as a steric and/or electrostatic filter that attenuates the miscoding potential of 8oG by normally interfering with the binding of 8oG in a syn conformation that pairs with dATP.
About this Structure
1ZYQ is a Protein complex structure of sequences from Bacteriophage t7 and Escherichia coli with and as ligands. Active as DNA-directed DNA polymerase, with EC number 2.7.7.7 Full crystallographic information is available from OCA.
Reference
A lysine residue in the fingers subdomain of T7 DNA polymerase modulates the miscoding potential of 8-oxo-7,8-dihydroguanosine., Brieba LG, Kokoska RJ, Bebenek K, Kunkel TA, Ellenberger T, Structure. 2005 Nov;13(11):1653-9. PMID:16271888
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