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Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
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Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage

Published on: August 21, 2021

[Interactions of pro- and eukaryotic DNA repair enzymes with oligodeoxyribonucleotides containing clustered lesions]

K V Starostin, A A Ishchenko, D O Zharkov

    Molekuliarnaia Biologiia
    |March 27, 2007
    PubMed

    Insights

    DNA repair enzymes like Fpg and OGG1 show reduced efficiency when oxoGuanine (oxoG) and abasic sites (F) are adjacent. Enzyme activity is less affected by lesion proximity for Apnl and Nfo, with increasing distance improving function.

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • DNA Repair Mechanisms

    Context:

    • Oxidative DNA damage, including 8-oxoguanine (oxoG), is implicated in aging and diseases.
    • DNA glycosylases and abasic site endonucleases are crucial for repairing such damage.
    • Understanding enzyme kinetics and substrate interactions is key to deciphering repair pathways.

    Purpose:

    • To investigate the impact of dual DNA lesions (oxoG and abasic site analog F) on the activity of specific DNA repair enzymes.
    • To determine how the proximity and relative positions of these lesions affect enzyme affinity (KM) and catalytic rate (kcat).
    • To compare the responses of oxoG-DNA glycosylases (Fpg, OGG1) and abasic site endonucleases (Apnl, Nfo) to dual-lesion substrates.

    Summary:

    • Studies examined Escherichia coli Fpg, human OGG1, yeast Apnl, and E. coli Nfo interactions with DNA containing oxoG and tetrahydrofuran (F) lesions.
    • Fpg and OGG1 exhibited significantly reduced affinity and reaction rates when F was adjacent to oxoG.
    • Apnl and Nfo showed minimal changes in affinity but decreased reaction rates with adjacent lesions, with activity improving as lesion distance increased.

    Impact:

    • Reveals enzyme-specific sensitivities to the spatial arrangement of DNA lesions.
    • Provides insights into the substrate recognition and processing mechanisms of key DNA repair enzymes.
    • Contributes to understanding how DNA repair efficiency is modulated by the complexity of oxidative damage.

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