DNA footprinting with the hydroxyl radical.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• The Fenton reaction involving iron(II) EDTA and hydrogen peroxide is a powerful tool for DNA structural analysis.
• Ascorbate ion enhances the Fenton reaction's utility as a DNA structure probe.
• Understanding DNA recombination intermediates like the Holliday junction is crucial in molecular biology.

Purpose of the Study:

• To identify the active DNA-cleaving agent generated by the Fenton reaction system.
• To apply the Fenton reaction for determining the three-dimensional structure of the Holliday junction.
• To investigate the structural implications of the Holliday junction's pseudo-twofold symmetry.

Main Methods:

• Utilizing the Fenton reaction with iron(II) EDTA, hydrogen peroxide, and ascorbate ion.
• Analyzing DNA cleavage patterns generated by the Fenton reagent.
• Characterizing the structure of the Holliday junction through cleavage data.

Main Results:

• The Fenton reaction system produces a specific DNA cleaving agent.
• The cleavage pattern of the Holliday junction exhibits pseudo-twofold symmetry.
• This symmetry provides significant constraints on possible Holliday junction structures.

Conclusions:

• The Fenton reaction is a valuable method for probing DNA structure, particularly complex structures like the Holliday junction.
• The observed pseudo-twofold symmetry in Holliday junction cleavage patterns offers critical insights into its molecular architecture.
• Further structural elucidation of DNA recombination intermediates can be achieved using this chemical probe.