AFM-Based Quantification of Conformational Changes in DNA Caused by Reactive Oxygen Species

Radical induced modification of DNA plays an important role in many pathological pathways like cancer development, aging, etc. In this work, we quantify radical-induced DNA damage that causes transitions from double to single stranded DNA using atomic force microscopy (AFM). The plasmid pBR322 is attacked by free hydroxyl radicals that are produced by Fenton's reaction; the strength of the radical attack is controlled via the ratio of hydroxyl radical molecules to DNA base pairs. The extent of DNA modification is assessed by AFM tapping mode (TM) imaging of the plasmids (after adsorption onto PAH-functionalized mica) in air. As single stranded DNA chains (height similar to 2 angstrom) are much smaller than intact DNA strands (similar to 5 angstrom), their fraction can be quantified based on the height distribution, which allows a simplified data analysis in comparison to similar AFM-based approaches. It is found that the amount of damaged DNA strands increases with increasing strength of radical attack, and decreases if ROS scavengers like sodium acetate are added. Competition curves are calculated for the interaction of hydroxyl radicals with DNA and sodium acetate, which finally allows calculation of relative rate constants for the respective reactions.

Wilken, J.Universität Greifswald,University of Greifswald (författare)
Helm, C. A.Universität Greifswald,University of Greifswald (författare)
Block, Stephan,1978Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)blocks (författare)
Universität GreifswaldChalmers tekniska högskola (creator_code:org_t)

Ingår i:Journal of Physical Chemistry B: American Chemical Society (ACS)119:1, s. 25-321520-52071520-6106

Av författaren/redakt...: Berg, F.; Wilken, J.; Helm, C. A.; Block, Stephan, ...

Om ämnet

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.