Related Experiment Video

Updated: Jul 8, 2026

Design and Synthesis of a Reconfigurable DNA Accordion Rack
07:44

Design and Synthesis of a Reconfigurable DNA Accordion Rack

Published on: August 15, 2018

DNA interstrand cross-link formation initiated by reaction between singlet oxygen and a modified nucleotide

In Seok Hong1, Marc M Greenberg

  • 1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.

Journal of the American Chemical Society
|July 28, 2005
PubMed

Insights

Singlet oxygen oxidizes a thymidine analogue, creating DNA interstrand cross-links. This finding suggests the analogue could enhance photodynamic therapy effectiveness against cancer.

Area of Science:

  • Biochemistry
  • Photodynamic Therapy
  • DNA Damage

Background:

  • DNA is a primary target for anti-cancer drugs.
  • DNA damage occurs via oxidation or alkylation.
  • Interstrand DNA cross-links are cytotoxic, as seen with mitomycin C.

Purpose of the Study:

  • To investigate the reaction of DNA with singlet oxygen.
  • To explore the potential of a thymidine analogue in photodynamic therapy.

Main Methods:

  • Oxidation of a thymidine analogue (2) using singlet oxygen.
  • Analysis of the resulting DNA modifications.

Main Results:

  • The thymidine analogue (2) rearranges to a methide upon oxidation by singlet oxygen.
  • This rearrangement results in the formation of DNA-DNA interstrand cross-links.

Conclusions:

  • Singlet oxygen-induced oxidation of thymidine analogue 2 forms DNA interstrand cross-links.
  • This novel mechanism indicates that analogue 2 may serve as an effective adjuvant in photodynamic therapy.

More Related Videos

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad5106:24

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51

Published on: February 13, 2019

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation09:26

DNA-Tethered RNA Polymerase for Programmable In vitro Transcription and Molecular Computation

Published on: December 29, 2021

Related Concept Videos

DNA Replication02:40

DNA Replication

DNA replication involves the separation of the two strands of the double helix, with each strand serving as a template from which the new complementary strand is copied.  After replication, each double-stranded DNA includes one parental or “old” strand and one “new” strand. This is known as semiconservative replication. The resulting DNA molecules have the same sequence and are divided equally into the two daughter cells.
Replication in Prokaryotes
DNA replication uses a large number of...
The DNA Replication Fork01:02

The DNA Replication Fork

An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork.   Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Gene Conversion02:08

Gene Conversion

Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
The DNA Replication Fork01:02

The DNA Replication Fork

An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork.   Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
Homologous Recombination02:31

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...