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Updated: Jun 17, 2026
10:59
Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
Published on: August 21, 2021
Ultraviolet-driven self-repair in chimeric d(GAUU) outcompetes damage formation
Sarah J Crucilla1,2, Jia Zeng2,3, Dian Ding3
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
Chemical Communications (Cambridge, England)
|June 16, 2026
Summary
Ancient nucleic acids survived early Earth
Area of Science:
- Astrobiology
- Biochemistry
- Molecular Biology
Background:
- Nucleic acid stability under UV irradiation was crucial for life's persistence.
- Pyrimidines are susceptible to UV photodamage, forming cyclobutane pyrimidine dimers (CPDs).
- Intrinsic UV-induced self-repair may have aided ancient nucleic acid survival before enzymatic repair.
Purpose of the Study:
- Investigate the disparity in self-repair quantum yields between RNA and DNA sequences.
- Experimentally measure the self-repair of a chimeric sequence d(GAU=U).
- Determine the factors influencing UV self-repair efficiency in oligonucleotides.
Main Methods:
- UV/Vis spectroscopy
- High-performance liquid chromatography (HPLC) analysis
- Measurement of quantum yields for damage formation and self-repair.
Main Results:
- The chimeric sequence d(GAU=U) exhibited a self-repair quantum yield of 1.16% upon 285 nm irradiation.
- This yield surpassed previously reported self-repair yields for canonical RNA and DNA sequences.
- The self-repair quantum yield of d(GAUU) exceeded its net damage quantum yield, a novel finding.
- Damage formation in d(UU) showed a damage quantum yield of 0.74%.
Conclusions:
- Backbone conformation and sequence significantly influence nucleic acid self-repair.
- Chimeric sequences demonstrate enhanced UV resistance compared to canonical sequences.
- Chimeric sequences may have served as UV-resistant precursors to modern DNA.
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