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5-Formyluracil-induced perturbations of DNA function
Daniel K Rogstad1, Jiyoung Heo, Nagarajan Vaidehi
1Department of Biochemistry and Microbiology, Loma Linda University School of Medicine, Loma Linda, California 92350, USA.
Biochemistry
|May 12, 2004
Summary
Oxidation of thymine creates 5-formyluracil (FoU), a DNA lesion that is unstable and mutagenic. FoU can miscode and disrupt DNA-protein interactions, impacting DNA function.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Oxidation of thymine in DNA generates 5-formyluracil (FoU).
- FoU is a mutagenic and chemically unstable DNA lesion.
- Understanding FoU's impact on DNA function is crucial.
Purpose of the Study:
- To investigate how 5-formyluracil (FoU) perturbs DNA function.
- To assess the stability and DNA-protein interaction effects of FoU.
Main Methods:
- Synthesis of oligonucleotides containing site-specific FoU.
- Measurement of FoU glycosidic bond half-life under physiological conditions.
- Analysis of AP-1 transcription factor binding to FoU-containing DNA using titration calorimetry.
- Molecular modeling of FoU-containing DNA duplexes.
Main Results:
- The FoU glycosidic bond half-life in single-stranded DNA is approximately 148 days, significantly shorter than thymine.
- FoU substitution for thymine inhibits AP-1 (c-Jun homodimer) binding by ~0.6 kcal/mol.
- Molecular modeling shows the FoU formyl group is partially solvent-accessible.
- No cross-linking was observed with AP-1 or polylysine.
Conclusions:
- FoU residues are sufficiently stable in DNA to cause miscoding and interfere with DNA-protein interactions.
- The instability and disruptive potential of FoU highlight its role in DNA damage and mutagenesis.
- FoU's impact on DNA-protein binding, like AP-1, suggests broader functional consequences.