Structural and biochemical impact of C8-aryl-guanine adducts within the NarI recognition DNA sequence: Influence of aryl ring size on targeted and semi-targeted mutagenicity


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Date

2014-12-01

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Chemical mutagens with an aromatic ring system may be enzymatically transformed to afford aryl radical species that preferentially react at the C8-site of 2′-deoxyguanosine (dG). The resulting carbon-linked C8-aryl-dG adduct possesses altered biophysical and genetic coding properties compared to the precursor nucleoside. Described herein are structural and in vitro mutagenicity studies of a series of fluorescent C8-aryl-dG analogues that differ in aryl ring size and are representative of authentic DNA adducts. These structural mimics have been inserted into a hotspot sequence for frameshift mutations, namely, the reiterated G3-position of the NarI sequence within 12mer (NarI(12)) and 22mer (NarI(22)) oligonucleotides. In the NarI(12) duplexes, the C8-aryl-dG adducts display a preference for adopting an anti-conformation opposite C, despite the strong syn preference of the free nucleoside. Using the NarI(22) sequence as a template for DNA synthesis in vitro, mutagenicity of the C8-aryl-dG adducts was assayed with representative high-fidelity replicative versus lesion bypass Y-family DNA polymerases, namely, Escherichia coli pol I Klenow fragment exo− (Kf−) and Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4). Our experiments provide a basis for a model involving a two-base slippage and subsequent realignment process to relate the miscoding properties of C-linked C8-aryl-dG adducts with their chemical structures.

Publication status

published

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Volume

42 (21)

Pages / Article No.

13405 - 13421

Publisher

Oxford University Press

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Edition / version

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Organisational unit

03853 - Sturla, Shana / Sturla, Shana check_circle

Notes

It was possible to publish this article open access thanks to a Swiss National Licence with the publisher

Funding

260341 - DNA Adduct Molecular Probes: Elucidating the Diet-Cancer Connection at Chemical Resolution (EC)

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