Oxidative damage to DNA is important amongst humans because it can lead to aging and cancer, and oxidative damage occurs mostly at the site of the easily oxidized base, guanine. When guanine becomes a radical, it can lead to a DNA-protein crosslink. We wanted to determine if we could inhibit the formation of oxidative DNA damage done by adding tryptophan based antioxidants. We specifically tested the ability of tryptamine to inhibit the damage within DNA and determined the concentration and conditions at which tryptamine functions best. Light was used to irradiate and excite Ru(phen)2dppz2+, making it an Ru3+ that oxidizes guanine and makes a guanine radical, which can react to make a DNA-protein crosslink or a form of oxidized guanine. Assays used for detecting the DNA-protein crosslinking were chloroform extraction assay and gel electrophoresis. In the absence of tryptamine, a large amount of DNA-protein crosslinking was observed in both experiments. In the presence of tryptamine, only a small amount of DNA-protein crosslinking was seen. To confirm that the tryptamine played a role in redox repair of DNA, we carried out transient-absorption measurements and observed a long-lived signal at 510 nm, consistent with the formation of an indole radical. The use of tryptophan based antioxidants inhibits DNA oxidative damage and the amount of DNA-protein crosslinking present.

Inhibition of oxidative DNA-protein crosslinking via tryptophan based antioxidants

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.