Probing electron-induced bond cleavage at the single-molecule level using DNA origami templates

摘要

Low-energy electrons (LEEs) play an important role in nanolithography, atmospheric chemistry, and DNA radiation damage. Previously, the cleavage of specific chemical bonds triggered by LEEs has been demonstrated in a variety of small organic molecules such as halogenated benzenes and DNA nucleobases. Here we present a strategy that allows for the first time to visualize the electron-induced dissociation of single chemical bonds within complex, but well-defined self-assembled DNA nanostructures. We employ atomic force microscopy to image and quantify LEE-induced bond dissociations within specifically designed oligonucleotide targets that are attached to DNA origami templates. In this way, we use a highly selective approach to compare the efficiency of the electron-induced dissociation of a single disulfide bond with the more complex cleavage of the DNA backbone within a Π dinucleotide sequence. This novel technique enables the fast and parallel determination of DNA strand break yields with unprecedented control over the DNA';s primary and secondary structure. Thus the detailed investigation of DNA radiation damage in its most natural environment, e.g., DNA nucleosomes constituting the chromatin, now becomes feasible.

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