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Updated: Jul 24, 2025

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51
Published on: February 13, 2019
Switching between DNA binding modes with a photo- and redox-active DNA-targeting ligand, part II: the influence of
Christoph Dohmen1, Heiko Ihmels1
1Department of Chemistry - Biology, University of Siegen, and Center of Micro- and Nanochemistry and (Bio)Technology (Cμ), Adolf-Reichwein-Str. 2, 57068 Siegen, Germany. ihmels@chemie.uni-siegen.de.
Abstract:
A disulfide-functionalized photoactive DNA ligand is presented that enables the control of its DNA-binding properties by a combination of a photocycloaddition reaction and the redox reactivity of the sulfide/disulfide functionalities. In particular, the initially applied ligand binds to DNA by a combination of intercalation and groove-binding of separate benzo[b]quinolizinium units. The association to DNA is interrupted by an intramolecular [4 + 4] photocycloaddition to the non-binding head-to-head cyclomers. In turn, the subsequent cleavage of these cyclomers with dithiothreitol (DTT) regains temporarily a DNA-intercalating benzoquinolizinium ligand that is eventually converted into a non-binding benzothiophene. As a special feature, this sequence of controlled deactivation, recovery and internal shut-off of DNA-binding properties can be performed directly in the presence of DNA.
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