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| - | [[Image:1x9m.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1x9m.png|left|200px]] |
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| | {{STRUCTURE_1x9m| PDB=1x9m | SCENE= }} | | {{STRUCTURE_1x9m| PDB=1x9m | SCENE= }} |
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| - | '''T7 DNA polymerase in complex with an N-2-acetylaminofluorene-adducted DNA'''
| + | ===T7 DNA polymerase in complex with an N-2-acetylaminofluorene-adducted DNA=== |
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| - | ==Overview==
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| - | The carcinogen 2-acetylaminofluorene forms two major DNA adducts: N-(2'-deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-AAF) and its deacetylated derivative, N-(2'-deoxyguanosin-8-yl)-2-aminofluorene (dG-AF). Although the dG-AAF and dG-AF adducts are distinguished only by the presence or absence of an acetyl group, they have profoundly different effects on DNA replication. dG-AAF poses a strong block to DNA synthesis and primarily induces frameshift mutations in bacteria, resulting in the loss of one or two nucleotides during replication past the lesion. dG-AF is less toxic and more easily bypassed by DNA polymerases, albeit with an increased frequency of misincorporation opposite the lesion, primarily resulting in G --> T transversions. We present three crystal structures of bacteriophage T7 DNA polymerase replication complexes, one with dG-AAF in the templating position and two others with dG-AF in the templating position. Our crystallographic data suggest why a dG-AAF adduct blocks replication more strongly than does a dG-AF adduct and provide a possible explanation for frameshift mutagenesis during replication bypass of a dG-AAF adduct. The dG-AAF nucleoside adopts a syn conformation that facilitates the intercalation of its fluorene ring into a hydrophobic pocket on the surface of the fingers subdomain and locks the fingers in an open, inactive conformation. In contrast, the dG-AF base at the templating position is not well defined by the electron density, consistent with weak binding to the polymerase and a possible interchange of this adduct between the syn and anti conformations. | + | The line below this paragraph, {{ABSTRACT_PUBMED_15528277}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15528277 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15528277}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: N-2-acetylaminofluorene]] | | [[Category: N-2-acetylaminofluorene]] |
| | [[Category: Replication block]] | | [[Category: Replication block]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 14:44:59 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 02:06:25 2008'' |
Revision as of 23:06, 28 July 2008
Template:STRUCTURE 1x9m
T7 DNA polymerase in complex with an N-2-acetylaminofluorene-adducted DNA
Template:ABSTRACT PUBMED 15528277
About this Structure
1X9M is a Protein complex structure of sequences from Enterobacteria phage t7 and Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structures of 2-acetylaminofluorene and 2-aminofluorene in complex with T7 DNA polymerase reveal mechanisms of mutagenesis., Dutta S, Li Y, Johnson D, Dzantiev L, Richardson CC, Romano LJ, Ellenberger T, Proc Natl Acad Sci U S A. 2004 Nov 16;101(46):16186-91. Epub 2004 Nov 4. PMID:15528277
Page seeded by OCA on Tue Jul 29 02:06:25 2008
