Related Experiment Video
Updated: Apr 8, 2026

Characterizing DNA Repair Processes at Transient and Long-lasting Double-strand DNA Breaks by Immunofluorescence Microscopy
Published on: June 8, 2018
Dewar Lesion Formation in Single- and Double-Stranded DNA is Quenched by Neighboring Bases
Dominik B Bucher1,2, Bert M Pilles1, Thomas Carell2
1†BioMolecular Optics and Center for Integrated Protein Science, Ludwig-Maximilians- Universität München Oettingenstrasse 67, 80538 München, Germany.
Abstract:
UV-induced Dewar lesion formation is investigated in single- and double-stranded oligonucleotides with ultrafast vibrational spectroscopy. The quantum yield for the conversion of the (6-4) lesion to the Dewar isomer in DNA strands is reduced by a factor of 4 in comparison to model dinucleotides. Time resolved spectroscopy reveals a fast process in the excited state with spectral characteristics of bases which are adjacent to the excited (6-4) lesion. These kinetic components have large amplitudes and indicate that an additional quenching channel acts in the stranded DNA systems and reduces the Dewar formation yield. Presumably relaxation evolves via a charge transfer to the neighboring guanine and the paired cytosine participates in a double-stranded oligomer. Changes in the decay of the relaxed excited electronic state of the (6-4) chromophore point to modifications in the excited state energy landscape which may lead to an additional reduction of the Dewar formation yield.
Related Concept Videos
Nucleotide Excision Repair
Nucleotide Excision Repair
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Fixing Double-strand Breaks
Fixing Double-strand Breaks
Single-Strand DNA Binding Proteins
Translesion DNA Polymerases
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...

